Tom Lipton Yes, even an old dog like me can learn, after leaving a comment on metric threading with Keith F. tonight, I stumbled on your tutorial on just that, it is a work around that I have never seen before WOW-COOL. I have had to teach customers (angry customers) that had been sold a lathe that should do inch metric threading and I had to teach that stop and backup routine for years and I see this and it is so simple, can’t believe that I hadn’t thought of it! JON
Thank you so very much for posting this. I’m new to machining, had my lathe less than a year and was having the worst trouble cutting my first metric thread. Your video really saved the day :)
Damn. I'm a prototype machinist, and I didn't know about this. I was always under the impression that you had to keep it engaged the whole time. You just made my life easier.
I had considered this threading method (but the opposite way i.e. cutting inch thread on a metric lathe) soon after its launch many years ago, but regarded it too complicated and forgot about it. But recently it started to bother me again. I re-watched the video and understood it better. Oh yes I tried it and what a sweet safe way it is to turn a thread to a shoulder. I am very grateful to you and your source for this excellent method. There are really no more steps than threading normal way. You only re-engage on the reverse instead on the forward. It is just that easy and fearless.Thank you Tom.
This is a super technique which should have been standard fare in all textbooks published in the last 50 years. For us who live in a metric standard country and purchase regularly from the States (Imperial dimension tools and supplies) this procedure is worth its weight in gold. I really enjoyed your demonstration (very well done) and continue to enjoy the TH-cam machining community's generosity. Great stuff!
Absolutely brilliant my friend! I wish I would have thought of that a long time ago, as it would have made many a job easier. This is great for threading to a shoulder, but for through threading like I did recently I'll just keep it engaged. Thanks for doing our homework for us, and showing us another way to getter done. Thanks bud! Adam
Hey Adam, I was so excited when I tried it. It was like finding a new Starrett tool on the sidewalk in perfect condition. It just put a smile on my face. Talk to you soon. Tom
Not necessarily. i don't see any reason to use the old fashioned way of setting the compound at 29 degrees and then letting one side of the tool burnish rather than cut. Might be OK with HSS tooling but most inserts don't do their best work with a very small depth of cut. That's what results when using the compound to advance. The left hand side of the tool would cut but the right hand side would burnish & heat. What do you gain by using the compound?
Very Nice and Cool. That was nice and clever, but exhausting too. You are on the top of the world after completing a successful project not without a feeling a high. Thanks for the Video.
I've used this for quite a while. I actually figured this out on my own because I thread a bunch of metric threads on my inch lead screw lathe in my ATV/Motorcycle shop. One problem I also had was that my metric side didn't cut 1.25mm or 2.50mm threads which are pretty common in the metric world. After seeing Keith Fenner calculate that a 20TPI is practically the same as 1.25mm! Now I can cut them all. Thanks for all of your great detailed videos. Andy Maul
On older machines with lots of backlash etc, ensure that you engage the 1/2 nut with the same amount of closure if it is variable. The other is to wind back enough off the thread for the start and I put a little of drag on the hand wheel to take up any backlash in the system, then I let go of the hand wheel before the cut starts. The main thing is not to change any gearing for when reversing etc. My other tip is to cut at a speed that you are comfortable with stopping by disengaging the 1/2 nut. This is very useful when cutting internal threads to a blind shoulder etc. I was shown this as an apprentice back in 1982. A great video .
I've been cutting metric threads for years and have never thought of this trick. I will certainly give it a go on the next job. It should releive the blood pressure problem of having to wind out the tool and disengage the clutch and still have to worry about the inertia of the machine and the risk of having a prang.with the tool runing into the shoulder. Thanks heaps.
Thanks Tom, excellent demo! Had just got done reading Conrad article and I noticed this video had come up in my search window and BAM, now to the video😀. Awesome job! Now threading metric to a ridge won't be so tense😎
Thank you very much!!! That is really what I have searched for, no calculation, just the most simple and useful method for my chinese lathe without a brake :D
Thanks for the video. I just picked up a set of Metric gears for my SB 10L and was thinking about how to go about using them. I figured it out about 2 seconds before you showed it. Thanks again!
Very cool Tom, Always great to learn something new after all the years we put in to our profession. After I learn something, I always comment back, "Now I'm smarter today than I was yesterday" Thanks for sharing! I'll be coming to the open house, looking forward to meeting you and yours. Ray.
Pretty pleased with myself, I was wondering what the heck you were going to do, then I figured it out just before you said it. Brilliant idea! Now I just need to find a set of metric change gears for my old lathe (almost impossible)
Hi Tom, Good trick to not end up with a broken shoulder when working on a lathe with no pedal brake. I'll try for sure... Today is another good day where I've learned something new. Thanks, Pierre
Cool technique. I have become VERY dependent on the footbrake and jog button when doing such a thread. It's nice to take some of the pressure off by being able to release the half-nut. I shall use this in future. Thanks to the original poster and yourself for the excellent demo. Colin
Conrad Hoffman is a pretty good guy, I have had a couple of conversations with him over at PM, didnt know he had this up though, thanks for pointing it out and the great demo. Stan
This will come in very handy if I ever end up with a lathe capable of cutting metric threads, or even one capable of reverse without flipping wires for that matter! lol Thanks for the great educational demonstration.
Awesome tips here! I’ve been wondering how cut metric threads on my small American lathe. As a fairly new hobby machinists, I’ve learned a ton from you and absolutely love the channel!!! 👍
Clever, really good idea for machines that don''t have a foot brake (probably not the proper term for it) And, for anyone doing metric threads- due to backlash, don't forget to pull your tool out before reversing! Quite a few winners I've seen forget to do that, not realizing how much slop some machines have
Thanks for sharing that technique Tom. Just recently I was faced with the same scenario of metric threading up to a shoulder. To cut back on the stress factor I set up a micro switch mounted on a magnet on the lathe bed that would shut down the lathe motor just in time to allow the tool to coast up to the shoulder. Worked great but this would have saved me some screwing around.
Hey Chris, I feel the same way. Somebody mentioned you can hand turn the spindle with the half nut engaged if the thread is in easy material and fine enough. Cheers, Tom
If the motor is 3 phase and the gearbox is industrial strength you can get very good repeatability from a micro switch by using "plug reversing", which is basically the same idea as the ancient dodge of stopping a steam engine by throwing it straight into reverse. Plug reversing used to be in common use on turret lathes, at least in the UK, and the motors were often fitted with a "zero speed sensing" switch, which would turn the power off at the moment rotation ceased, effectively using the motor as a very powerful brake. However for threading this switch is not necessary, as you actually want to reverse the spindle rotation to get back for the next pass. The concept works particularly well with a swingup toolholder, a modern idea based on an ancient one (the clapper box used on shapers and planers) which makes it unnecessary to withdraw the tool for the return to the next pass. It makes it possible to thread at CNC spindle speeds, at least if you have a VFD (where decel and accel can be set to make reversing a bit less instant, hence easier on the gearbox). It can even eliminate the need for a thread relief groove, at least when using HSS (except in very hard materials) If this idea had been commonly known a hundred years ago, the need for such things as threading dials, single tooth dog clutches, rapid retract toolposts and crosslides, ball-stop crossfeed, snaptap threading devices etc etc, would have been much more limited -- mainly I would guess being needed for internal single point threadcutting, where a swingup toolholder is impracticable, or for hobby lathes with single phase motors or lightly built gearboxes.
Very good technique for people to see. Like most of my generation I was trained to never uncouple unless absolutely necessary and there are times when it is much easier to be able to momentarily uncouple as sometimes we were cutting inch threads on a metric lathe, ha ha - same problem. I will add that when one cuts one of the rare fractional pitches (11-1/2 TPI comes to mind here) that your demonstrated technique will prevent the "doubling" that can occur. Good job.
Hi Robert, Yes you have the inverse problem. I am upset that I learned this trick after so many years of doing it the hard way. Thanks for the comment. Cheers, Tom
That's one for the collection for sure! Thanks for putting it in living color...TH-cam is great. My eye caught something during the video that I wondered if you would give us a better look at? That is the rack for your quick change tool holders. Thanks! Dru
I have one of these moriseiki lathes. When I got it, it was set up for metric, with 36 drive gear. I had to replace with 72 drive gear. Am now learning how to operate this machine. I love the machine. Bought it out of a shop for $1000.00 dollars, and they thought it was european with european power. I built my own 3 phase unit and run it fine. My serial is 990.
Thanks for the great advice Tom. Got some adaptors to turn tomorrow so going to give it a go. I have always been in the habit of keeping the half nuts locked at all times when cutting a metric thread.
I'm new to actually doing any machining. I've been studying for a couple years but just got a lathe this spring. I've only done a few threading operations whatsoever. As I've read about going metric threading on my old Logan 10" it always seemed to me like this method you show should be perfectly doable. But everything I read said that you MUST leave the half nut engaged to do metric threading on an inch leadscrew. Thank you for confirming my "naïve" suspicion. :)
Hi Jon, This is why this technique is so important. It really shows that the must leave half nuts engaged is not needed with a little care. Thanks for the comment. Cheers, Tom
This is a good "trick". Thanks. I have not done much threading, just a 3/4"-8 LH SQ thread on some chuck screws, and some 1/4"-20 threads where I turned the tool upside down and used reverse. I kept the half-nut engaged for the 8 TPI because it was too hard to hit the dial tick with a 16 TPI leadscrew and a little 64 tooth thread dial on my little HF 9x20.
Not watched you for a while Tom but this is a top tip was struggling with doing the same this on a lathe I recently changed and and handles a half nut lever was on opposite sides,thanks again for all the videos you post Dan
Great video, I have a metric lathe and was struggling to cut an imperial thread until I discovered that the threading dial wouldn't work so used the keeping the half nuts closed method. I'm thinking that this method will also work for cutting imperial threads on a metric lathe, will try it. Many thanks.
My first threading project ever on my Grizzly G4000 9x19 lathe is 2.5mm pitch metric threads. For converting Intex pool filter proprietary threads to 1.5 MPT, you can buy an [chinese] adapter off Amazon; the 1.5 MPT is tolerable, but the 'intex' end should be 59mm as measured from a stock male thread, and the knock-offs are 58mm (shrinkage?) and blow off inopportunely due to partial engagement. I said enough is enough, I will just do it myself. There is no brake on my lathe, so about 1.5 turns from the end, you need to un-power and coast; the threads need to be right up to the 'hex' (octo) nut on the PVC. I quickly figured out you needed to keep the half nut engaged to stay in the same thread track, but kept lightly hitting the 'nut'. Your technique is BRILLIANT; I just went out to the shop and did a test cut x3 passes, and it works PERFECTLY! Nobel Prize 🏆🏆 for lathe cutting for you 🙂 HUGE Thank you.
This is GREAT I have always left the 1/2 nut engaged on metric threads in the past but this makes perfect sense!!! Another note on most lathes you can grab a faster spindle speed on the reverse if you are cutting a long thread, as the feed drivetrain is driven directly off the spindle and doesn't care what gear the spindle is in. We have a couple of lathes with clutches that run faster in reverse for this exact purpose. PS you can turn the spindle by hand for real finiky right up to a shoulder super fine rifle scope type threads
Good Trick. Another addition would be to set the Cross slide dial handle at 9:00 position zero the dial or mark it, (so down on the handle is always out, away from part) on every cut. Feed into part at 29.5 degrees with the compound slide. Then you wouldn't have to remember how deep you were on the last cut. I always marked my cuts on the compound dial with a marker. You wouldn't even use the DRO. (much faster) Actually that's the "classical" way to do it. On very large, course threads, it is the only really efficient way to do it. With the classical way one is actually turning the thread not gouging it out, which is what going straight in, actually is. I do like your thinking Tom, I've learned to think the same. When I found a better way, that's my new way! Doesn't matter who showed me. I once had my day saved by a janitor in 1980, who solved a chatter problem on a long small dia shaft I was doing with a trick he knew, and I didn't know. I never asked how he knew, but I tried it, and it worked.
Ok, so what was the chatter trick you learned? I learned how to drill perfect circles (holes) in sheet metal by placing a very small folded rag right over the drill bit and then drilling down on that through the metal.
That particular time I mentioned, it was to put the tool a bit above center. Another time in 1983, I was facing a large diameter flange (about 30" X 1.050 thick diameter) flange welded to a 3" bearing diameter shaft. This produced an annoying, high pitched squeal. An Allis Chalmers veteran of 35 years, (this was not at Allis Chalmers at the time), walked up and thru a mighty mag base which stuck to the back side of the flange and the squealing stopped. This was a new idea to me and I used it many times thereafter. (Harmonics) So if you encounter squealing or chatter, "sometimes" placing a magnet on the side of the boring bar or other tool, or on the part itself, will stop the harmonics. I later was given job (at a different shop) to turn 40" to 50" long, (1/4") wall ,5-6" diameter steel tubes. The old guys there laughed and told me that I had been stuck with the "shit" job, because in the past they had to stand and follow the carriage holding a lead hammer against the part during the whole turning process to prevent chatter(harmonics). So I removed the upright shaft from two indicator bases and I placed the magnetic bases inside the tube at each end on opposite sides (when the old guys weren't looking) and started turning. For effect, I sat on the bench while I turned the chatter free tubes with my legs flapping in the breeze looking bored, and smoking a cigarette (times have changed) all the while I could see these two older guys off to the side looking on, with a "WTF" look on their faces. The "shit job" ,turned into the best job in the shop, as I had very many of these tubes to turn. The tubes had a large tolerance on the O.D. but they could have no chatter marks. The moral of the story? Although I had learned the principle of the fix from a very experienced old guy myself, these "old guys" made the mistake of thinking a younger guy knew less than they did on every matter, simply because he was younger. The proper, and only right way, to view machining, is to always consider it a learning experience all the way up till your last day. When one thinks he "knows it all", he or she, is ineffective thereafter. There's nothing wrong with being proud of your effort to learn and your accomplishments, but it's necessary to have this primary restraint. There is an old saying in the Biz. "There are machinists with 20 years experience and then there are machinists with 1 years experience, 20 times". I actually met a pair of the latter, and proved that saying to be true, in Arkansas circa 2003. Although I was chief toolmaker, I couldn't have taught those two guys to run out of a burning building. Dumb and Dumber were steadfastly bound to stay that way, on their own volition. (Ain't no yankee gunna tell me nothin!), at least they were right on one thing. I hope this may help you Tom. After 40+ years I retired in January. I'm done learning about machining. Although I still show up with one of my three machinist sons at a shop, for special projects. I read books, play guitar, and other things now.................... Keep pounding,,(I just, had to say that...)
Fantastic answer.... I'll certainly keep it in mind. I have used bicycle tube wrapped around shafts welded to plate when the harmonics began. Sometimes with success and sometimes not. Also lead soldering sticks attached to boring bars but never the magnets and first chance I get, I'll give them a go. Here is a question you may be able to answer. I've been setting up a quick program (excel) to determine the depth of thread depths using a bit of trig and with using the compound to do all the 'work' as it were. Bit hard to explain my question other than this. When turning a piece of stock to take a (Eg), 12 mm thread * 1.75 where the recommended Major Dia (Max) is 11.97mm.... Can you see a reason why I should turn that stock to a dia of 12.35mm to then cut the thread to a depth of 50 Thou (1.26mm)? In other words and in all thread cutting operations, does the stock begin as a size a fraction larger in Dia than the Major Dia Max? Then as the correct thread depth is achieved, this Dia reduces down to what it should be? Refer to "Maryland Metrics Thread Data Charts" on the net. I like solving all manner of math problems using a hand held PC or the excel and then simply punching in whatever needs I have at the time and the answers get calculated. I've done that to date with all and any contour cut ever known to man in fitting piping together to give no gaps whatsoever when fitting pipe as structural pieces and or intersections. Just have a think on that question about Dia's and I'd be interested to get your thoughts. 12.35mm or 11.97mm?
Tom I don't quite understand the question. But it was always standard practice to turn the diameter .005 under the nominal, beforehand when threading. I'll bet there is a chart showing thread depth on the internet. As there is on some thread tool setting gauges. The anti harmonic solutions don't always work but when they do!...wooohooo!... :-) I've used the inner tube solution also. Double lead threads can be done by fixture or by a rotation of a gear on the manual lathe. Pain in the .... The acme thread screw sleeves(up down) on old milling machines require double lead. One more thing about harmonics. Back in the 70's I was boring out Rexnord "lock Post" hydraulic cylinders for rock crushing machines.( funny, years later I machined many of the large eccentric bushings for the very same rock crushing machines, at another job shop), anyhow,The bore was about 8" diameter and 30" deep if I recall correctly. The owner of the company came buy and he asked me if I knew the purpose of the many lengthwise and dissimilarly milled out sections on the large boring bar I was using. I said no. He said it was to reduce harmonics. Apparently harmonics are more prevalent in symmetrical situations. So break up the symmetry, whether by shape or magnetism. I didn't know the magnet trick at the time. P.S. I've got a funny story about turning cable drums and another one about using a steady rest with brass pads if you'd like to hear such nostalgic dribble...
Yep, hard to explain in text. www.boltscience.com/pages/screw3.htm The Crest line is just lower than the apex. So do we begin the threading process using the apex dia is what I'm wondering? And yes I fully understand convention saying .005 under nominal but could it be .005 over? Anyone's input here?
Damn, why have I never thought of that. And there is nothing stopping you from doing the same at both ends of the thread. I wish I'd watched that a month ago, I had a part to thread with very little room at each end of the thread. It was very stressful
you can do the same idea but still manually move the carriage back if you are using a carriage stop. i do this on inside threading for when i cant have a relief cut. like on the inside of a pressure vessel. ( relief cut can make wall thickness to small) you unlock the halfnut then shut off the machine, then roll back the carriage to the start position then start the machine in revers without the halfnut engaged until it lines up with number you started with on the threading gauge. set cutter to depth reengage halfnut then start machine.
Tom, that is a fantastic trick! Honestly I have never cut a metric thread with a lathe, however since I have seen you talk about it in some of your videos I feel ready to try one. In the shop at school I only have one lathe (a Nardini) capable of metric threads. My primary lathe at home is a 20"x36" American Tool Works circa 1903 and I am fairly certain none of these were ever built to do metric threads.
Hey John, Thanks for stopping by. I was excited when I learned this little gem. I can't say I thought of it myself. Thanks for the comment. Cheers, Tom
Nice demo Tom. Always learning! So much to consider for a seemingly simple little plug:) Keep in mind that there is a 3mm radius on the top flange of the transformer, so you can stop the thread 1mm short of the shoulder if you like.. You are getting me very excited now!
Hey Nick, Fenner had the million dollar steady rest series. Now I have the 500Kb (kilo buck) brass plug. Everybody is going to really want to see where this goes. Cheers, Tom
Hi Tom, now that's my kind of shop tip, awesome, man, if I did a video showing that, I'd get tattooed. Just a continuous stream of comments of how I'd be doing it all wrong. And it seemed you did it as a straight on thread as well, I get accused of that all the time, though I'm actually only cutting the leading edge. As you say, this is great practical information to be shared and used, I like to use the term "bumblebee engineering" Great video as always! Uh oh, I just realized, I guess I'm going to have to look for my threading dial now if I'm going to use this, fair enough. Thanks Tom, I'm trying to get caught up on all the videos I've been missing. Mike
Hey Michael, I don't know what they put in the water around your place but it sure makes for troll magnets to stick to you. I generally do compound feed but in this case for a shallow thread in easy material it doesn't matter. If the tool fits the groove its right. Incidentally down a bore with a small thread relief against a shoulder radial feed is your only option. Its done all the time. Your threading dial is under the pile of chips on the carriage to your right. Thanks for the comment. Best, Tom
Very eloquent Tom, maybe another good reason to follow your advice and de-chip the shop, repel the troll magnets LOL Thanks for the practical information reinforcement!
Any tips on cutting internal metric threads in a blind hole? I would like to cut away from the chuck for speed and safety. (I have 300 parts to do). I thought about setting up a dial indicator to zero when I'm at the bottom of the hole and engaging the half nut on the same mark on the thread dial. Please tell me a better way if you can think of it. Thanks
Good tip! It also seems that after you pullout and shut down the lathe, you could manually move the carriage until the thread dial lines up, engage the half-nut, then go in reverse. Should be the same. I'll have to check it out. It may be easier for those with a fine lead screw.
That is so stupid simple it's pathetic. Why did it take so many years for someone to think of this, and explain it so much earlier? Wonderful video, as always.
Hi Tom , Thanks for your nice vid , in our shop we dont use chasing dial at all , just all time engaging and reversing at the and of the pass with out stopping the machine. (metric) i hope you understand what i'm saying .
Not quite sure why you are waiting for the half nut line to appear if you reverse it will start in the same Groove each time you go backwards and forwards?
interesting video Tom .....but what i find most interesting is the very early lathes had very interesting features like dept stop etc..that more modern lathes including my cholchester does not...yea the Hendey lathes and maybe some others really were setup to do these kinds of jobs...
Hey Lawrence, The Monarch lathes have a really slick threading setup on them as well. Not quite as extensive and elaborate as a Hardinge but darn useful. cheers, Tom
I too am having much difficulty cutting a metric thread on a standardized lathe. Standard threads L and R no problem. And this is a great trick for keeping that position on the lead screw. I understand why you would need to do this when cutting a metric thread just fine. But what I don't understand is how to set up the change gears that are made for standard size threads to cut for example a 1.5mm thread? How do you get the right gear ratio? maybe you can explain that to us Tom. Thank you for making your videos and putting them out there.
I think it would be a good habit to do all threading in this sequence just so you are used to it, Could you use a different number on the dial each time to wear the screw evenly?
Hi Max, I don't think it matters which number you use. You end up with the same groove position regardless. You cannot change numbers mid stream. For a second part however you could change the reference number. Cheers, Tom
I have an idea for those cutting threads without a thread dial. (Mine is missing) The thread dial indicates the phase relation between the spindle and the drive screw. So I think that one could start by marking the carriage with a Sharpie at the bed with the half nut engaged AND by marking the lathe chuck at 12:00. Now begin the threading pass, at thread end disengage half nut, stop motor. Next turn the chuck by hand to the 12:00 position, crank apron back to starting point mark and engage half nut. Start motor, cut the next pass, repeat. I have not yet tried this but I expect it to work.
Hi Daniel, Your trick might work for normal threading but will not work for metric threading with an inch lead screw. The relationship between the chuck and lead screw rotation is not factorable. This is why you generally have to keep the half nut engaged for the entire threading cycle. You can keep the index correct for small rotations but not for major resets. Hope this makes sense. Thanks for the comment. Cheers, Tom
Hum,... I understand your comment - but not yet convinced. It seems that if one can re-create the initial conditions it must work. Now I think what you are implying is that if the chuck is returned to 12:00 and the half nut is then engaged that the apron may move slightly since the modulus of rotation is not an integer relation. In that case you would need to notice that the apron is not at the initial position. Adding an indicator to the bed measuring the position of the apron and then rotating the chuck to the correct 12:00 rotation would be needed. Do you follow?
You are very close, but also mark the lead screw against the lathe frame so you can manually turn the lead screw to the original starting position then re-engage half nuts. The method shown is best but if you don't have reverse try this.
Neat trick. Works well if you have a spindle brake. Those of us with simple lathes may have to count rotations while the spindle spins to a stop. I do have a VFD on my Craftsman. I'll try it on mine. With the VFD it does do some braking on the stop but I bet I'll still get near a full rotation of the dial on mine.;)
rcdieselrc My VFD trips out on over current if I set the braking time much shorter. I have upped the current limit but it still must coast to half speed or so before applying the brake. I could optimize it more but also don't want to worry about the chuck unscrewing ;)
Hi Scott, No need to even use the brake. Once the half nut is disengaged there is no rush. It takes a long time for a full rev of the threading dial. Cheers, Tom
Hi Tom, Just wanted to say what a pleasure it is watching your videos. Your attention to detail and quality of workmanship is second to none! One thing which I am interested to know is that when you were threading, you advanced with the cross slide and not the compound. I haven't yet needed to thread on the lathe yet (machining is a hobby for me) but I was under the impression that you advance with the compound to reduce chatter etc. Is it due to the fact you are machining brass that this is possible without causing chatter? Regards Rob
Hi Rob, Its not necessary to use the compound when threading. Direct infeed works fine. Sometimes there is an advantage to use the compound such as very large threads where chatter is a problem. Its sometimes easier to keep track of your advancement with the compound as well. Both methods are valid and work fine. Thanks for the comment. Cheers, Tom
Tom, Noticed that five or six people have inquired about advancing depth of cut with the cross-feed vice the compound. Using the cross-feed resulting in a plunge cut, cutting with both sides of the tool or using the compound set at 29 degrees, cutting with only the leading edge of the tool. I’m wondering… maybe it does not matter much with soft materials and possibly using the compound would result in a better finish with hard materials. Your thoughts on this point would be greatly valued. TKS for the vid. Kind Regards, Brad
Hi Hedron, We call those Doubleboost lights after the famous British explorer that braved the wild zombie hordes that dwell at Ikea eating Swedish meatballs. Cheers, Tom
Great Video, thanks Tom, Just one question I was taught then when cutting threads to do the cut adjustment with the compound not the cross slide, is this a better way?
Hey Mike, You can go either way. For small fine threads the cross feed is quicker. The advantage is you can easily track where you are in relation to the minor diameter. Thanks for the comment. Cheers, Tom
@@byfordbarnard2264 And the tool is mostly cutting on the leading edge, taking the slack out of the lead screw. Kind of like we lock the carriage when parting, the tool would have a mind of it's own.
A great little work around, maybe I should make myself a thread dial for my metric lathe! On my Emco Compact 8, I have no options, keep the half nuts closed! Regards, Matthew
Hello Oxtoolco, This was a very well balanced video, filmed in real time which is the very best way to show it. However you seem to have got it all wrong from what I saw of the film, you have the compound slide correctly set at half the thread angle, but you are incrementing with the cross slide handle, this does away which the whole reason for setting over the compound slide, which is to be cutting only on the front edge of the tool. I have used this method for the past 40 years, although not at these revs, well done for surviving!
Hi French, Thanks for the comment. I pretty much leave my compound set at that angle all the time to keep it out of my way. So I didn't actually set it to do this video. I do use the compound for larger threads in tougher materials. For little threads and a nice rigid machine you can go either way and be fine. So got it all wrong might be a little over the top. The tool is perfectly capable to cut on both edge at the same time. If you do what most guys do and infeed a thou or so with the cross slide as your last pass to polish both sides of the thread wall you are basically doing the same thing. So you saw it worked fine right? Maybe do some experiments with your machine and tooling and see how it works for you. Cheers, Tom
+justfakeit888 On my lathe there is a chart inside the back door for the belts that shows the correct settings for metric pitches. It also requires a change gear. Thanks for the comment. Cheers, Tom
+justfakeit888 If I had a lot of metric threading to do I would get another manual lathe or possibly CNC that was setup from the getgo for metric threads. Thanks for the comment. Cheers, Tom
After watching this, it's such an obvious solution. Makes me question my whole life. Many thanks to Conrad and youse.
That is what I love about this trade - the learning curve never flattens out .
Good tip.
After a couple of broken hearts I never disengaged the halfnut all these years. Thank you for showing me how!!
Tom Lipton
Yes, even an old dog like me can learn,
after leaving a comment on metric threading with Keith F. tonight, I stumbled on your
tutorial on just that, it is a work around that I have never seen before
WOW-COOL. I have had to teach customers (angry customers) that had been sold a
lathe that should do inch metric threading and I had to teach that stop and backup routine for years and I see this and it is so simple, can’t believe that I hadn’t thought of it!
JON
Hi Jon,
I felt the same way when I first saw it. I was mad because of all those years of doing it the hard way. Thanks for the comment.
Cheers,
Tom
Thank you so very much for posting this. I’m new to machining, had my lathe less than a year and was having the worst trouble cutting my first metric thread. Your video really saved the day :)
Damn. I'm a prototype machinist, and I didn't know about this. I was always under the impression that you had to keep it engaged the whole time. You just made my life easier.
Very neat trick. This is so obvious when pointed out, thank you
1.000.000 thanks to you Tom, I have learned so many things from you..!!!!!
I just had one of those "Why didn't I think of that" moments... Outstanding tip and explanation! Thanks for sharing Tom...
Hey John,
I felt the same way. Its so simple but apparently not obvious.
Cheers,
Tom
I had considered this threading method (but the opposite way i.e. cutting inch thread on a metric lathe) soon after its launch many years ago, but regarded it too complicated and forgot about it. But recently it started to bother me again. I re-watched the video and understood it better. Oh yes I tried it and what a sweet safe way it is to turn a thread to a shoulder. I am very grateful to you and your source for this excellent method. There are really no more steps than threading normal way. You only re-engage on the reverse instead on the forward. It is just that easy and fearless.Thank you Tom.
This is a super technique which should have been standard fare in all textbooks published in the last 50 years. For us who live in a metric standard country and purchase regularly from the States (Imperial dimension tools and supplies) this procedure is worth its weight in gold. I really enjoyed your demonstration (very well done) and continue to enjoy the TH-cam machining community's generosity. Great stuff!
Hey Jim,
Thanks for the comment. I was as excited as you when I tried it myself. Its great to learn a new trick and add to your toolbox.
Cheers,
Tom
Tom, Just wanted to say thanks for making this video. I was going crazy trying to cut metric threads. This was the answer!
Absolutely brilliant my friend! I wish I would have thought of that a long time ago, as it would have made many a job easier. This is great for threading to a shoulder, but for through threading like I did recently I'll just keep it engaged.
Thanks for doing our homework for us, and showing us another way to getter done.
Thanks bud!
Adam
Hey Adam,
I was so excited when I tried it. It was like finding a new Starrett tool on the sidewalk in perfect condition. It just put a smile on my face.
Talk to you soon.
Tom
He does it wrong way. He should adjusts depth at compound slide rather than at cross slide.
Not necessarily. i don't see any reason to use the old fashioned way of setting the compound at 29 degrees and then letting one side of the tool burnish rather than cut. Might be OK with HSS tooling but most inserts don't do their best work with a very small depth of cut. That's what results when using the compound to advance. The left hand side of the tool would cut but the right hand side would burnish & heat. What do you gain by using the compound?
Very Nice and Cool. That was nice and clever, but exhausting too. You are on the top of the world after completing a successful project not without a feeling a high. Thanks for the Video.
I've used this for quite a while. I actually figured this out on my own because I thread a bunch of metric threads on my inch lead screw lathe in my ATV/Motorcycle shop. One problem I also had was that my metric side didn't cut 1.25mm or 2.50mm threads which are pretty common in the metric world. After seeing Keith Fenner calculate that a 20TPI is practically the same as 1.25mm! Now I can cut them all. Thanks for all of your great detailed videos.
Andy Maul
Hey Andy,
Thanks for the comment. Its a great trick.
Cheers,
Tom
Super. a new tool in my box. I am thankful nearly everyday for youTube... I know there are those who curse it... but... not me.
On older machines with lots of backlash etc, ensure that you engage the 1/2 nut with the same amount of closure if it is variable. The other is to wind back enough off the thread for the start and I put a little of drag on the hand wheel to take up any backlash in the system, then I let go of the hand wheel before the cut starts. The main thing is not to change any gearing for when reversing etc. My other tip is to cut at a speed that you are comfortable with stopping by disengaging the 1/2 nut. This is very useful when cutting internal threads to a blind shoulder etc. I was shown this as an apprentice back in 1982. A great video .
I've been cutting metric threads for years and have never thought of this trick. I will certainly give it a go on the next job. It should releive the blood pressure problem of having to wind out the tool and disengage the clutch and still have to worry about the inertia of the machine and the risk of having a prang.with the tool runing into the shoulder.
Thanks heaps.
Hi Robert,
I know the feeling. This is so simple its a wonder its not more common. Thanks for the comment.
Cheers,
Tom
Many thanks for sharing Tom!
No more "Brake & Jog" for metric single point threading!
Very good demo,
Ray
Thanks Tom, excellent demo! Had just got done reading Conrad article and I noticed this video had come up in my search window and BAM, now to the video😀. Awesome job! Now threading metric to a ridge won't be so tense😎
Hi Rambler,
Conrad has some great stuff on his site. This is so simple but escaped me for many years. Thanks for the comment.
Cheers,
Tom
Thank you very much!!! That is really what I have searched for, no calculation, just the most simple and useful method for my chinese lathe without a brake :D
Thanks for the video. I just picked up a set of Metric gears for my SB 10L and was thinking about how to go about using them. I figured it out about 2 seconds before you showed it. Thanks again!
Hi Precision,
Thanks for the comment.
Cheers,
Tom
Very cool Tom,
Always great to learn something new after all the years we put in to our profession. After I learn something, I always comment back,
"Now I'm smarter today than I was yesterday"
Thanks for sharing!
I'll be coming to the open house, looking forward to meeting you and yours.
Ray.
Hey Ray,
Thanks for the comment. See you soon.
Cheers,
Tom
Pretty pleased with myself, I was wondering what the heck you were going to do, then I figured it out just before you said it. Brilliant idea! Now I just need to find a set of metric change gears for my old lathe (almost impossible)
Hi Tom,
Good trick to not end up with a broken shoulder when working on a lathe with no pedal brake. I'll try for sure...
Today is another good day where I've learned something new.
Thanks,
Pierre
Hi Pierre,
I was happy to learn this as well. I was grinning like crazy.
Cheers,
Tom
Cool technique. I have become VERY dependent on the footbrake and jog button when doing such a thread. It's nice to take some of the pressure off by being able to release the half-nut. I shall use this in future. Thanks to the original poster and yourself for the excellent demo.
Colin
Hey Colin,
Thanks for the comment. You can actually coast for quite a while. I use the foot brake out of habit.
Cheers,
Tom
Wow, just ran across this video. I could have used that a few months ago. Definitely a great technique. Thanks for sharing.
Conrad Hoffman is a pretty good guy, I have had a couple of conversations with him over at PM, didnt know he had this up though, thanks for pointing it out and the great demo.
Stan
Hi Stan,
What is his handle over on PM? I have seen his article on thread tool honing before but must have missed this gem.
Cheers,
Tom
Oddly enough .. Conrad Hoffman is his user name
very good, just fighting a metric threading problem a couple months ago. will definately try this. THANKS
Thanks Tom. Makes perfect sense, as all the good ideas do.
This is a great trick, I don't cut many metric threads but when I do I am going to give it a try, thanks.
Glad you like it. Thanks for the comment.
Cheers,
Tom
This will come in very handy if I ever end up with a lathe capable of cutting metric threads, or even one capable of reverse without flipping wires for that matter! lol Thanks for the great educational demonstration.
Hey Brian,
Just turn your lathe around 180 degrees, instant reverse. Its all in the observer.
Cheers,
Tom
At 9000lbs of lathe I think I will just stand on the other side. :-) That should work too. lol
Awesome tips here! I’ve been wondering how cut metric threads on my small American lathe. As a fairly new hobby machinists, I’ve learned a ton from you and absolutely love the channel!!! 👍
Clever, really good idea for machines that don''t have a foot brake (probably not the proper term for it)
And, for anyone doing metric threads- due to backlash, don't forget to pull your tool out before reversing! Quite a few winners I've seen forget to do that, not realizing how much slop some machines have
Hi Jay,
Thanks for the comment.
Cheers,
Tom
Thanks for sharing that technique Tom. Just recently I was faced with the same scenario of metric threading up to a shoulder. To cut back on the stress factor I set up a micro switch mounted on a magnet on the lathe bed that would shut down the lathe motor just in time to allow the tool to coast up to the shoulder. Worked great but this would have saved me some screwing around.
Hey Chris,
I feel the same way. Somebody mentioned you can hand turn the spindle with the half nut engaged if the thread is in easy material and fine enough.
Cheers,
Tom
If the motor is 3 phase and the gearbox is industrial strength you can get very good repeatability from a micro switch by using "plug reversing", which is basically the same idea as the ancient dodge of stopping a steam engine by throwing it straight into reverse. Plug reversing used to be in common use on turret lathes, at least in the UK, and the motors were often fitted with a "zero speed sensing" switch, which would turn the power off at the moment rotation ceased, effectively using the motor as a very powerful brake.
However for threading this switch is not necessary, as you actually want to reverse the spindle rotation to get back for the next pass.
The concept works particularly well with a swingup toolholder, a modern idea based on an ancient one (the clapper box used on shapers and planers) which makes it unnecessary to withdraw the tool for the return to the next pass. It makes it possible to thread at CNC spindle speeds, at least if you have a VFD (where decel and accel can be set to make reversing a bit less instant, hence easier on the gearbox).
It can even eliminate the need for a thread relief groove, at least when using HSS (except in very hard materials)
If this idea had been commonly known a hundred years ago, the need for such things as threading dials, single tooth dog clutches, rapid retract toolposts and crosslides, ball-stop crossfeed, snaptap threading devices etc etc, would have been much more limited -- mainly I would guess being needed for internal single point threadcutting, where a swingup toolholder is impracticable, or for hobby lathes with single phase motors or lightly built gearboxes.
Very good technique for people to see. Like most of my generation I was trained to never uncouple unless absolutely necessary and there are times when it is much easier to be able to momentarily uncouple as sometimes we were cutting inch threads on a metric lathe, ha ha - same problem. I will add that when one cuts one of the rare fractional pitches (11-1/2 TPI comes to mind here) that your demonstrated technique will prevent the "doubling" that can occur. Good job.
Hi Robert,
Yes you have the inverse problem. I am upset that I learned this trick after so many years of doing it the hard way. Thanks for the comment.
Cheers,
Tom
That's one for the collection for sure! Thanks for putting it in living color...TH-cam is great. My eye caught something during the video that I wondered if you would give us a better look at? That is the rack for your quick change tool holders.
Thanks!
Dru
Hey Dru,
I did a segment in one of the meatloafs on the tool rack. Search tool rack or toolholder rack and see if it catches it.
Cheers,
Tom
Nice video. I also enjoyed your book very much, Tom.
Hi Shobar,
Thanks for the nice comment and support.
Cheers,
Tom
I have one of these moriseiki lathes. When I got it, it was set up for metric, with 36 drive gear. I had to replace with 72 drive gear. Am now learning how to operate this machine. I love the machine. Bought it out of a shop for $1000.00 dollars, and they thought it was european with european power. I built my own 3 phase unit and run it fine. My serial is 990.
Thanks for the great advice Tom. Got some adaptors to turn tomorrow so going to give it a go. I have always been in the habit of keeping the half nuts locked at all times when cutting a metric thread.
Hi Andrew,
Well. How did it work out? Thanks for the comment.
Cheers,
Tom
I'm new to actually doing any machining. I've been studying for a couple years but just got a lathe this spring. I've only done a few threading operations whatsoever. As I've read about going metric threading on my old Logan 10" it always seemed to me like this method you show should be perfectly doable. But everything I read said that you MUST leave the half nut engaged to do metric threading on an inch leadscrew. Thank you for confirming my "naïve" suspicion. :)
Hi Jon,
This is why this technique is so important. It really shows that the must leave half nuts engaged is not needed with a little care. Thanks for the comment.
Cheers,
Tom
This is a good "trick". Thanks. I have not done much threading, just a 3/4"-8 LH SQ thread on some chuck screws, and some 1/4"-20 threads where I turned the tool upside down and used reverse. I kept the half-nut engaged for the 8 TPI because it was too hard to hit the dial tick with a 16 TPI leadscrew and a little 64 tooth thread dial on my little HF 9x20.
Your a clever guy!! you know that? Nobody thought at this before. Salute from England from a Transilvanian guy :))))
Hi Gigi,
Thanks for the comment.
Cheers,
Tom
Thank you for that neat trick, Bob
Not watched you for a while Tom but this is a top tip was struggling with doing the same this on a lathe I recently changed and and handles a half nut lever was on opposite sides,thanks again for all the videos you post Dan
Many thanks Tom, something we should have all thought ourselves...
Great video, I have a metric lathe and was struggling to cut an imperial thread until I discovered that the threading dial wouldn't work so used the keeping the half nuts closed method. I'm thinking that this method will also work for cutting imperial threads on a metric lathe, will try it. Many thanks.
My first threading project ever on my Grizzly G4000 9x19 lathe is 2.5mm pitch metric threads. For converting Intex pool filter proprietary threads to 1.5 MPT, you can buy an [chinese] adapter off Amazon; the 1.5 MPT is tolerable, but the 'intex' end should be 59mm as measured from a stock male thread, and the knock-offs are 58mm (shrinkage?) and blow off inopportunely due to partial engagement. I said enough is enough, I will just do it myself. There is no brake on my lathe, so about 1.5 turns from the end, you need to un-power and coast; the threads need to be right up to the 'hex' (octo) nut on the PVC. I quickly figured out you needed to keep the half nut engaged to stay in the same thread track, but kept lightly hitting the 'nut'. Your technique is BRILLIANT; I just went out to the shop and did a test cut x3 passes, and it works PERFECTLY! Nobel Prize 🏆🏆 for lathe cutting for you 🙂
HUGE Thank you.
new student here, smart man there. I too am no spring chicken but love learning new things on anything
Very good,I have am old craftsman lathe I am going to try that the next time I need to cut some metric threads
Thanks again
Thanks very much. Awesome idea I can’t wait to try it
This is GREAT I have always left the 1/2 nut engaged on metric threads
in the past but this makes perfect sense!!!
Another note on most lathes you can grab a faster spindle speed on the reverse
if you are cutting a long thread, as the feed drivetrain is driven directly off the spindle
and doesn't care what gear the spindle is in.
We have a couple of lathes with clutches that run faster in reverse for this exact purpose.
PS you can turn the spindle by hand for real finiky right up to a shoulder super fine
rifle scope type threads
Hey Gent,
You did the same thing I did. I went, well crap that is a cool trick. Why didn't I think of that years ago.
Cheers,
Tom
Good Trick.
Another addition would be to set the Cross slide dial handle at 9:00 position zero the dial or mark it, (so down on the handle is always out, away from part) on every cut. Feed into part at 29.5 degrees with the compound slide. Then you wouldn't have to remember how deep you were on the last cut. I always marked my cuts on the compound dial with a marker. You wouldn't even use the DRO. (much faster) Actually that's the "classical" way to do it. On very large, course threads, it is the only really efficient way to do it. With the classical way one is actually turning the thread not gouging it out, which is what going straight in, actually is.
I do like your thinking Tom, I've learned to think the same. When I found a better way, that's my new way! Doesn't matter who showed me. I once had my day saved by a janitor in 1980, who solved a chatter problem on a long small dia shaft I was doing with a trick he knew, and I didn't know. I never asked how he knew, but I tried it, and it worked.
Ok, so what was the chatter trick you learned? I learned how to drill perfect circles (holes) in sheet metal by placing a very small folded rag right over the drill bit and then drilling down on that through the metal.
That particular time I mentioned, it was to put the tool a bit above center. Another time in 1983, I was facing a large diameter flange (about 30" X 1.050 thick diameter) flange welded to a 3" bearing diameter shaft. This produced an annoying, high pitched squeal. An Allis Chalmers veteran of 35 years, (this was not at Allis Chalmers at the time), walked up and thru a mighty mag base which stuck to the back side of the flange and the squealing stopped.
This was a new idea to me and I used it many times thereafter. (Harmonics) So if you encounter squealing or chatter, "sometimes" placing a magnet on the side of the boring bar or other tool, or on the part itself, will stop the harmonics.
I later was given job (at a different shop) to turn 40" to 50" long, (1/4") wall ,5-6" diameter steel tubes. The old guys there laughed and told me that I had been stuck with the "shit" job, because in the past they had to stand and follow the carriage holding a lead hammer against the part during the whole turning process to prevent chatter(harmonics). So I removed the upright shaft from two indicator bases and I placed the magnetic bases inside the tube at each end on opposite sides (when the old guys weren't looking) and started turning. For effect, I sat on the bench while I turned the chatter free tubes with my legs flapping in the breeze looking bored, and smoking a cigarette (times have changed) all the while I could see these two older guys off to the side looking on, with a "WTF" look on their faces. The "shit job" ,turned into the best job in the shop, as I had very many of these tubes to turn. The tubes had a large tolerance on the O.D. but they could have no chatter marks. The moral of the story? Although I had learned the principle of the fix from a very experienced old guy myself, these "old guys" made the mistake of thinking a younger guy knew less than they did on every matter, simply because he was younger. The proper, and only right way, to view machining, is to always consider it a learning experience all the way up till your last day. When one thinks he "knows it all", he or she, is ineffective thereafter. There's nothing wrong with being proud of your effort to learn and your accomplishments, but it's necessary to have this primary restraint.
There is an old saying in the Biz.
"There are machinists with 20 years experience and then there are machinists with 1 years experience, 20 times". I actually met a pair of the latter, and proved that saying to be true, in Arkansas circa 2003. Although I was chief toolmaker, I couldn't have taught those two guys to run out of a burning building. Dumb and Dumber were steadfastly bound to stay that way, on their own volition. (Ain't no yankee gunna tell me nothin!), at least they were right on one thing.
I hope this may help you Tom. After 40+ years I retired in January. I'm done learning about machining. Although I still show up with one of my three machinist sons at a shop, for special projects. I read books, play guitar, and other things now.................... Keep pounding,,(I just, had to say that...)
Fantastic answer.... I'll certainly keep it in mind. I have used bicycle tube wrapped around shafts welded to plate when the harmonics began. Sometimes with success and sometimes not. Also lead soldering sticks attached to boring bars but never the magnets and first chance I get, I'll give them a go.
Here is a question you may be able to answer. I've been setting up a quick program (excel) to determine the depth of thread depths using a bit of trig and with using the compound to do all the 'work' as it were. Bit hard to explain my question other than this. When turning a piece of stock to take a (Eg), 12 mm thread * 1.75 where the recommended Major Dia (Max) is 11.97mm.... Can you see a reason why I should turn that stock to a dia of 12.35mm to then cut the thread to a depth of 50 Thou (1.26mm)? In other words and in all thread cutting operations, does the stock begin as a size a fraction larger in Dia than the Major Dia Max? Then as the correct thread depth is achieved, this Dia reduces down to what it should be? Refer to "Maryland Metrics Thread Data Charts" on the net.
I like solving all manner of math problems using a hand held PC or the excel and then simply punching in whatever needs I have at the time and the answers get calculated. I've done that to date with all and any contour cut ever known to man in fitting piping together to give no gaps whatsoever when fitting pipe as structural pieces and or intersections. Just have a think on that question about Dia's and I'd be interested to get your thoughts. 12.35mm or 11.97mm?
Tom I don't quite understand the question. But it was always standard practice to turn the diameter .005 under the nominal, beforehand when threading. I'll bet there is a chart showing thread depth on the internet. As there is on some thread tool setting gauges. The anti harmonic solutions don't always work but when they do!...wooohooo!... :-) I've used the inner tube solution also. Double lead threads can be done by fixture or by a rotation of a gear on the manual lathe. Pain in the ....
The acme thread screw sleeves(up down) on old milling machines require double lead.
One more thing about harmonics. Back in the 70's I was boring out Rexnord "lock Post" hydraulic cylinders
for rock crushing machines.( funny, years later I machined many of the large eccentric bushings for the very same rock crushing machines, at another job shop), anyhow,The bore was about 8" diameter and 30" deep if I recall correctly. The owner of the company came buy and he asked me if I knew the purpose
of the many lengthwise and dissimilarly milled out sections on the large boring bar I was using. I said no. He said it was to reduce harmonics. Apparently harmonics are more prevalent in symmetrical situations. So break up the symmetry, whether by shape or magnetism. I didn't know the magnet trick at the time.
P.S. I've got a funny story about turning cable drums and another one about using a steady rest with brass pads if you'd like to hear such nostalgic dribble...
Yep, hard to explain in text. www.boltscience.com/pages/screw3.htm
The Crest line is just lower than the apex. So do we begin the threading process using the apex dia is what I'm wondering? And yes I fully understand convention saying .005 under nominal but could it be .005 over? Anyone's input here?
I like it, thanks Tom for the great demo.
Damn, why have I never thought of that. And there is nothing stopping you from doing the same at both ends of the thread.
I wish I'd watched that a month ago, I had a part to thread with very little room at each end of the thread. It was very stressful
you can do the same idea but still manually move the carriage back if you are using a carriage stop. i do this on inside threading for when i cant have a relief cut. like on the inside of a pressure vessel. ( relief cut can make wall thickness to small) you unlock the halfnut then shut off the machine, then roll back the carriage to the start position then start the machine in revers without the halfnut engaged until it lines up with number you started with on the threading gauge. set cutter to depth reengage halfnut then start machine.
Tom that is a really cool trick indeed.
Hey Bill,
I was stoked when I tried it. Its a keeper.
Cheers,
Tom
That is a very nice strategy!
Tom, that is a fantastic trick! Honestly I have never cut a metric thread with a lathe, however since I have seen you talk about it in some of your videos I feel ready to try one. In the shop at school I only have one lathe (a Nardini) capable of metric threads. My primary lathe at home is a 20"x36" American Tool Works circa 1903 and I am fairly certain none of these were ever built to do metric threads.
Hey Mike,
Well all I can say is you will cut one eventually. Wow 20 x 36 lathe. That's almost tuna can proportions.
Cheers,
Tom
I appreciate the meaningful titles
Thanks for that Tom Interesting method
Hey John,
Thanks for stopping by. I was excited when I learned this little gem. I can't say I thought of it myself. Thanks for the comment.
Cheers,
Tom
@@oxtoolco Doesn't matter, what matters is you took the time to get it out here, to help the suffering half-nutting hoardes.
Nice demo Tom. Always learning!
So much to consider for a seemingly simple little plug:)
Keep in mind that there is a 3mm radius on the top flange of the transformer, so you can stop the thread 1mm short of the shoulder if you like..
You are getting me very excited now!
Hey Nick,
Fenner had the million dollar steady rest series. Now I have the 500Kb (kilo buck) brass plug. Everybody is going to really want to see where this goes.
Cheers,
Tom
love it , I'm gonna do this tomorrow.. I always manually backed it off and never disengaged the half nut
Hi Tom, now that's my kind of shop tip, awesome, man, if I did a video showing that, I'd get tattooed. Just a continuous stream of comments of how I'd be doing it all wrong. And it seemed you did it as a straight on thread as well, I get accused of that all the time, though I'm actually only cutting the leading edge. As you say, this is great practical information to be shared and used, I like to use the term "bumblebee engineering" Great video as always! Uh oh, I just realized, I guess I'm going to have to look for my threading dial now if I'm going to use this, fair enough.
Thanks Tom, I'm trying to get caught up on all the videos I've been missing.
Mike
Hey Michael,
I don't know what they put in the water around your place but it sure makes for troll magnets to stick to you. I generally do compound feed but in this case for a shallow thread in easy material it doesn't matter. If the tool fits the groove its right. Incidentally down a bore with a small thread relief against a shoulder radial feed is your only option. Its done all the time.
Your threading dial is under the pile of chips on the carriage to your right.
Thanks for the comment.
Best,
Tom
Very eloquent Tom, maybe another good reason to follow your advice and de-chip the shop, repel the troll magnets LOL
Thanks for the practical information reinforcement!
Great video Tom!
Fantastic technique, just tried it ....just awesome...thank's for sharing. Would be great if you could show an internal thread with this technique.
Love the new intro and I enjoyed the tip. I hope I remember this when I buy my lathe. :)
Hey Wyatt,
I already forgot. I'll probably have to watch my own video again with that guy that says uhhhh all the time.
Cheers,
Tom
Thanks a lot for this! Great tip!
Thanks for sharing this trick and thank you TH-cam.
Wow, that's great! Isn't TH-cam awesome!
Thanks for posting this up Tom
Regards, Bill
Any tips on cutting internal metric threads in a blind hole? I would like to cut away from the chuck for speed and safety. (I have 300 parts to do). I thought about setting up a dial indicator to zero when I'm at the bottom of the hole and engaging the half nut on the same mark on the thread dial. Please tell me a better way if you can think of it. Thanks
Good tip! It also seems that after you pullout and shut down the lathe, you could manually move the carriage until the thread dial lines up, engage the half-nut, then go in reverse. Should be the same. I'll have to check it out. It may be easier for those with a fine lead screw.
Thanks for that Tom, getting the timing down will require some practice but that is a great idea. Gotta go make some chips now!
Hey Joe,
I practiced a little before I shot the video. I wanted to get the moves down.
Cheers,
Tom
fantastic tip! im a novice and im trying threading for the first time as soon as my inserts show up.
Hi Jason,
Thanks for the comment.
Cheers,
Tom
That is so stupid simple it's pathetic. Why did it take so many years for someone to think of this, and explain it so much earlier? Wonderful video, as always.
This was an awesome tip, thanks! Used this today and saved me a bunch of time.
Hi Tom , Thanks for your nice vid , in our shop we dont use chasing dial at all , just all time engaging and reversing at the and of the pass with out stopping the machine. (metric) i hope you understand what i'm saying .
Hi Nacer,
I do understand. For us metric handicaps we have to use special tricks to get it done. Thanks for the comment.
Cheers,
Tom
no matter how much you know, somebody else knows more
great video thanks for sharing!!
love the videos keep em' coming!!!
Hi Doc,
Thanks for the comment.
All the best,
Tom
Not quite sure why you are waiting for the half nut line to appear if you reverse it will start in the same Groove each time you go backwards and forwards?
great video thank you!
interesting video Tom .....but what i find most interesting is the very early lathes had very interesting features like dept stop etc..that more modern lathes including my cholchester does not...yea the Hendey lathes and maybe some others really were setup to do these kinds of jobs...
Hey Lawrence,
The Monarch lathes have a really slick threading setup on them as well. Not quite as extensive and elaborate as a Hardinge but darn useful.
cheers,
Tom
Thanks man that's awesome appreciate it
I too am having much difficulty cutting a metric thread on a standardized lathe. Standard threads L and R no problem. And this is a great trick for keeping that position on the lead screw. I understand why you would need to do this when cutting a metric thread just fine. But what I don't understand is how to set up the change gears that are made for standard size threads to cut for example a 1.5mm thread? How do you get the right gear ratio? maybe you can explain that to us Tom. Thank you for making your videos and putting them out there.
I'll be dipped in doo-doo if that's not a trick worth knowing! Thanks Tom.
Hey John,
That's one way to spin it.
Cheers,
Tom
Wow that's great, but I still can't figure how to set up the QC gearbox for the different TPI
I think it would be a good habit to do all threading in this sequence just so you are used to it, Could you use a different number on the dial each time to wear the screw evenly?
Hi Max,
I don't think it matters which number you use. You end up with the same groove position regardless. You cannot change numbers mid stream. For a second part however you could change the reference number.
Cheers,
Tom
oxtoolco Right, that's what I was thinking. Thanks for the confirmation.
Great video! Nice trick. I know someone who would have loved to know this before he messed up two parts that took quite a bit of work.
Hello Tom
Would you please explain how you set up your gearbox to get a metric thread out of an inch lead screw?
Thanks
Bill
I have an idea for those cutting threads without a thread dial. (Mine is missing)
The thread dial indicates the phase relation between the spindle and the drive screw.
So I think that one could start by marking the carriage with a Sharpie at the bed with the
half nut engaged AND by marking the lathe chuck at 12:00.
Now begin the threading pass, at thread end disengage half nut, stop motor.
Next turn the chuck by hand to the 12:00 position,
crank apron back to starting point mark and engage half nut.
Start motor, cut the next pass, repeat.
I have not yet tried this but I expect it to work.
Hi Daniel,
Your trick might work for normal threading but will not work for metric threading with an inch lead screw. The relationship between the chuck and lead screw rotation is not factorable. This is why you generally have to keep the half nut engaged for the entire threading cycle. You can keep the index correct for small rotations but not for major resets. Hope this makes sense. Thanks for the comment.
Cheers,
Tom
Hum,... I understand your comment - but not yet convinced. It seems that if one can re-create the initial conditions it must work. Now I think what you are implying is that if the chuck is returned to 12:00 and the
half nut is then engaged that the apron may move slightly since the modulus of rotation is not an integer relation. In that case you would need to notice that the apron is not at the initial position. Adding an indicator to the bed measuring the position of the apron and then rotating the chuck to the correct 12:00 rotation would be needed. Do you follow?
You are very close, but also mark the lead screw against the lathe frame so you can manually turn the lead screw to the original starting position then re-engage half nuts. The method shown is best but if you don't have reverse try this.
Neat trick.
Works well if you have a spindle brake. Those of us with simple lathes may have to count rotations while the spindle spins to a stop.
I do have a VFD on my Craftsman. I'll try it on mine. With the VFD it does do some braking on the stop but I bet I'll still get near a full rotation of the dial on mine.;)
Check your VFD settings. You should be able to increase braking current if it's adjustable.
Or for those of us with machines that doesn't stop (or start) on a dime. Brake or no brake :)
rcdieselrc My VFD trips out on over current if I set the braking time much shorter. I have upped the current limit but it still must coast to half speed or so before applying the brake. I could optimize it more but also don't want to worry about the chuck unscrewing ;)
Hi Scott,
No need to even use the brake. Once the half nut is disengaged there is no rush. It takes a long time for a full rev of the threading dial.
Cheers,
Tom
Hi Tom, Just wanted to say what a pleasure it is watching your videos. Your attention to detail and quality of workmanship is second to none! One thing which I am interested to know is that when you were threading, you advanced with the cross slide and not the compound. I haven't yet needed to thread on the lathe yet (machining is a hobby for me) but I was under the impression that you advance with the compound to reduce chatter etc. Is it due to the fact you are machining brass that this is possible without causing chatter? Regards Rob
Hi Rob,
Its not necessary to use the compound when threading. Direct infeed works fine. Sometimes there is an advantage to use the compound such as very large threads where chatter is a problem. Its sometimes easier to keep track of your advancement with the compound as well. Both methods are valid and work fine. Thanks for the comment.
Cheers,
Tom
Thanks for the video's. Where is the link to the article?
+Danny Jackson Hey Danny,
Let me google that for you. conradhoffman.com/metricthreading.htm Thanks for the comment.
Cheers,
Tom
Thank you
nice trick.
Tom,
Noticed that five or six people have inquired about advancing depth of cut with the cross-feed vice the compound. Using the cross-feed resulting in a plunge cut, cutting with both sides of the tool or using the compound set at 29 degrees, cutting with only the leading edge of the tool. I’m wondering… maybe it does not matter much with soft materials and possibly using the compound would result in a better finish with hard materials. Your thoughts on this point would be greatly valued. TKS for the vid.
Kind Regards,
Brad
Nice IKEA lamp on the mag base!
Hi Hedron,
We call those Doubleboost lights after the famous British explorer that braved the wild zombie hordes that dwell at Ikea eating Swedish meatballs.
Cheers,
Tom
Great Video, thanks Tom, Just one question I was taught then when cutting threads to do the cut adjustment with the compound not the cross slide, is this a better way?
Hey Mike,
You can go either way. For small fine threads the cross feed is quicker. The advantage is you can easily track where you are in relation to the minor diameter. Thanks for the comment.
Cheers,
Tom
Compound is supposed to be a stronger thread and not as much pressure when cutting big deep threads
@@byfordbarnard2264 And the tool is mostly cutting on the leading edge, taking the slack out of the lead screw. Kind of like we lock the carriage when parting, the tool would have a mind of it's own.
A great little work around, maybe I should make myself a thread dial for my metric lathe! On my Emco Compact 8, I have no options, keep the half nuts closed!
Regards, Matthew
Hey Matthew,
A thread dial would be a neat little project. You get to make a worm gear. Sounds like some fun to me.
Cheers,
Tom
oxtoolco As if I didn't have enough projects as it is!
Regards, Matthew
Hello Oxtoolco,
This was a very well balanced video, filmed in real time which is the very best way to show it. However you seem to have got it all wrong from what I saw of the film, you have the compound slide correctly set at half the thread angle, but you are incrementing with the cross slide handle, this does away which the whole reason for setting over the compound slide, which is to be cutting only on the front edge of the tool.
I have used this method for the past 40 years, although not at these revs, well done for surviving!
Hi French,
Thanks for the comment. I pretty much leave my compound set at that angle all the time to keep it out of my way. So I didn't actually set it to do this video. I do use the compound for larger threads in tougher materials. For little threads and a nice rigid machine you can go either way and be fine. So got it all wrong might be a little over the top. The tool is perfectly capable to cut on both edge at the same time. If you do what most guys do and infeed a thou or so with the cross slide as your last pass to polish both sides of the thread wall you are basically doing the same thing. So you saw it worked fine right? Maybe do some experiments with your machine and tooling and see how it works for you.
Cheers,
Tom
Hello,I can not understand why the TDI stops turning ? when cutting thread,how can you possible go back to a start point,using TDI.
This all makes sense to me, but how do you set the gearbox for a metric thread?
+justfakeit888 On my lathe there is a chart inside the back door for the belts that shows the correct settings for metric pitches. It also requires a change gear. Thanks for the comment.
Cheers,
Tom
I see. Another question--if you did a lot of metric threading, could you make a metric thread dial, or would you need a metric leadscrew too?
+justfakeit888 If I had a lot of metric threading to do I would get another manual lathe or possibly CNC that was setup from the getgo for metric threads. Thanks for the comment.
Cheers,
Tom