Machinists.....Tapping a thread on a Mill or Lathe?...Don't Do This !!!
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- เผยแพร่เมื่อ 16 เม.ย. 2024
- Just because a 'T' handle drives a tap, it doesn't mean it's giving you the best thread or security possible. This short video clearly illustrates the 'T' style handle may not be your best choice for smaller diameter threads when used a certain way. You really should watch this if you're new to machining, or experienced and really curious. Thanks.
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I am an enthusiastic hobby machinist. I've never had the benefit of personal instruction in the machine shop. Everything I know about machining comes from TH-cam, books, magazines and similar sources. Of course experience is the world's best (and sometimes harshest) teacher. I certainly didn't know what I didn't know on this one. Luckily, at least some of the TH-cam creators are true experts, with you being a prime example. Thank you so much for this, and all your efforts to put a dent in my ignorance.
You say how I feel also, with such style. Thanks!! I agree with you!
Yup! I agree. I had NO IDEA a tap T handle was not made ‘true’. Great tip.
👍 ! Great tip , surprised that this never occurred to me before, and surprised that I haven’t broken a lot of taps over the years.
The wobble of the tap as shown was more a result of a bad chuck in the tap holder than the hole at the back of the handle.
That's what it looked like to me, too. It looked like a banana, more wiggle in the middle than back at the end. If the misalignment was caused by a lack of a positive centre at the rear of the tap handle, that's where there should have been the most movement?
It also seems like something that could be more easily shown by chucking the tap handle into the lathe and reading off the runout of the OD vs ID...?
Disclaimer: absolutely *not* a machinist, but I reckon I can troubleshoot and interpret stuff pretty logically. The logic he's describing doesn't seem to match the results he's displaying here.
Disclaimer on the disclaimer: It seems like it'd be a pretty good idea to validate your tap follower and not just assume it has a precise centre, just on principle. That's absolutely a good point he's raising.
Damn it Joe ! I been doing this for years > down to #4-40 > haven't seemed to have a problem. But ur demo valid > shocked to see the tap run out that bad . Ya got me thinking. BTW, you & Mr Pete > best vids here on machine work
Balderdash!
Absolutely right! However, it's not the center, it's the jaws. We (retired from GTD) machine the entire body, including the center. At this point everything is concentric. The second OP is to drill, then saw the front to create the jaws. This is where the concentricity breaks down. The next OP is to spring temper the jaws, which causes the jaws go out of whack. This is where the real issue occurs. In theory, the cap is supposed to bring everything back into alignment. However, between the burrs from the saw cuts, and the slop between the threads in the cap and body, it doesn't allow the cap to pull everything back into alignment. Some brands are better than others, but as you state, bad idea!
Yeah na. I'd go for lil ER 11 Collets and turn it in one go, head upside down, parting last. Almost. Dunno yet. It's late lol. But that's the inspiration I got from this.
I don't think I've ever had my mind forcibly changed so quickly. You succeeded at this in only 10 minutes and 39 seconds. Congratulations Joe.
I've been using those T-handles for over 40 years and never thought about the handle being off that much. Thanks for the clearly demonstrated proof.
I'm glad you used non-magnetic aluminum! It doesn't look like people picked up on that!
Still puzzeled about the use of the plastic flim on the demagentizer. Never used it on mine! Lol.
I haf no idea my spring followers were reversable until this video. Thanks for sharing your knowledge and experience.
It just goes to show no matter how old you are we are always learning, that’s something I didn’t know thanks
I like your friend' saying: "It's impossible to know what you don't know" - that keeps us learning all the time without challenging the ego.
Well, well teach. I have never used the lathe as a tap driver. A tap held in the tailstock held by a drill chuck, yes. I have seen the physical dammage caused by power tapping has removed and dammaged man a hand so I just don't do it. The time saved isn't enough to worry about. Starting a tap, the right long taper to start and a gentle touch for me works just fine. I am a patient fellow by nature, I have always thought machinists were all like that are we not, LOL. Over the 45+ years of machining I can count on my hands how many taps I have broken and they we ALWAYS from alighnment issues. Keep em straight and be patient and enjoy the thing we love to do best. Thanks a bunch Texas. Great post and a bit of schooling today too. Thanks eh.
I'm one of those guys who didn't now about reversing the pointer on the tapguide. Thanks again, I always learn something watching you stuff
I didn't either
Great to hear!
Every time I watch one of your videos I learn something new. Thank you for sharing your knowledge.
Things you don't learn at school...
Thanks Joe.
I've been a maintenance machinist/mechanic for 40 years, and I have never used a T handle tap wrench in a lathe or mill. It never even occurred to me. Just put a drill chuck in the tailstock / spindle, grab the tap hand tight, and send it in at low speed. I have tapped hundreds if not thousands of holes using this method and I've NEVER broken a tap. I can hear the hate coming already. "4 flute taps are hand taps!" Yes. You can use this method to get them started, then switch to a dead center to support the tap and use a tap wrench (NOT T handle) to finish. Or if the tap is large enough, I just use an adjustable wrench. As long as the center is in the guide hole at the back of the tap, you're good. "Gun taps will fill the bottom of the hole with chips!" Also true. But you can back it out and clean out the chips if the hole isn't deep enough. I've used this method down to #4-40. Never had a problem.
Only problem is taps are hard and it slowly destroys drill chuck jaws.Collets are much better for holding taps.Most of the time i just spin the spindle or lathe chuck by hand (tailstock must be free ,not locked down).Its good enough for start Not a cnc speed of taping but it gets job done.
... and for the really small taps, use one of Joe's small knurled disk tap drivers between thumb and forefinger. Life savers!
Thanks for this video, I run a 5 axis mill that doesn't have a locating spindle, so no canned cycle, no tapping function. So often we use a spring loaded centre on the spindle to locate tapped holes on complex angles on parts, the issue is when we go below M8 we have to resort to the tapping handle with a centre, which has resulted in many poor threads and broken taps. Your method is so simple but will save us so much time and $, thanks.
Glad it helped
I used to just use the drill chuck to hold the tap. Then turn the lathe chuck by hand just to get it started straight a few threads, then finish by hand or with small threads just leave the tailstock unlocked and turn the lathe chuck by hand.
Every day is a school day. I never knew the spring centre was reversible.
Make all of your own tools, if you want precision. Remember that you can only be as precise, as the least precision piece, you are working with, and tolerances, stack up.
You're right about the centers being off, but it's sometimes on cheap wrenches, the jaw faces are not square. I made my own, and used them with centers in lathes, vertical mills, radial arm drills, for more than 60 years, and produced nice, square holes, every time. A long time ago, I started hating tapping, without a lail support.
Maybe my 40 year old T handle is one of the good ones. I have been doing this for 40 years and never had a problem.
Thanks for the advice Joe. I'll no longer do that anymore. I normally start the tap in the drill chuck and feed in into the part to get it started, then finish off with a T handle wrench, sprung loaded.
I'll be careful what I'm doing from now on.
I, like some of the other comments on here have tought myself how to machine parts so I'm loving your channel and the advice you give out. It is appreciated.
Interesting video and you made some very good points but the biggest point you made is that most tap handles are junk. Actually all tap handle to some degree are junk... just a bad design. With this being said, unless you are using a tap under a 6-32 tap the likelihood of breaking a tap is very slim and to a very large degree the tap will align itself. You can verify this by tapping with a wobbly handle, remove the wrench and turn the lathe on. The wobble will be very minimal. I have broke my fair share of taps but so far I have never broken one that is guided from the back of the handle unless the handle slip out of the guide. I made a tap wrench with a tube on the back that slips over a 3/8 countersink to eliminate this problem.
I definitely noticed that runout, even on a Starrett tap handle. Great video, thanks
Absolutely agree! I ruined a small valve body for a high-pressure Ingersoll Rand compressor that took me 6 hours to machine
" Im just a beginner " because i used a T handle that was a mile off. The center screw threads were off angle, and I couldn't figure out what I was doing wrong.
My old machinists friend set me straight. And greatings from McMurdo Station Antarctica. Home Houston Texas 😊
Thanks Joe!
I observed this phenomenon when tapping on my old drill press and blamed the drill press. After that I bought a hand tapping machine and never went back to using a tap guide in the drill press-even when I bought a new one.
On my lathe I just used the drill chuck in the tail stock to start it then switched to a tap handle to finish.
Outstanding video. One should never assume the precision of tooling, without testing. Been there done that.
Charlie
Joe, great video as always. I do a lot of threading with small sized taps for astronomical telescopes, mounts, and cameras so breaking one is always a risk and can be disastrous. One thing many don't realize is taps come in different types. The standard most common type has a taper to the thread cutters so it can be aligned somewhat as you start the operation. There are also bottom threading types that are designed to thread far down into a blind hole (one that doesn't go completely through the material) They have very minimal starting taper.You NEVER should start with that one. The other type has a much longer taper to help perfectly align the tap and those are the one you should start with to ensure your tap is perfectly aligned with the hole especially on small tap sizes. I buy my taps in the sets that include all three types for each thread size. I am now 77 years old but learned this from my teacher in a gunsmithing class 60 years ago. I had spent hours machining a bench rest rifle barrel and action that was blued and only thing left was to drill and tap for the scope mount. I was terrified all that work would be destroyed with a broken small tap. My instructor showed me his tricks and it was completed perfectly. The most critical thing is the start of the tapping operation... make sure the hole and tap are absolutely aligned. Also take the time to back the tap out several times to clean out all the bits of metal cuttings. It is tempting to get lazy and try to power the tap through when it gets a bit tight due to chip jamming. That is when things go south
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I am not a machinist - but I am a hobbyist who's been making parts for many years. I've never seen this addressed before. Thank you!
Thanks so much for this !! those pointed tap ends WERE the bane of my existence - I had no idea that was reversible
I made a lot of small stuff in my day, and used a lot of small taps. Broke quite a few and at some point noticed this same problem. It's much worse on tap handles labeled "General" than on ones from Starrett or other quality brands. I noticed another thing too. Take that tap handle apart. Look inside the part that is like a collet. Notice that it has more than four flats. Four at the tip and then four more further inside. Place the tap far enough inside that the inner four flats drive it and the outer four flats bear on the cylindrical part of the shank. Note how much more concentric it runs. This is only for taps that fit up inside like that but it definitely helps. Also, you can remake the main body of a cheap tap wrench much better if you chuck it in a four jaw and redo the "center" that it has for the tap guide to run in. Thanks Joe!
The Starrett chuck type (T handle) tap holders are beautifully made and have a separate, spring-loaded jaw assembly. (Similar to the chuck in an old woodworking brace.) This gives them a large size range and a good grip in my experience. However it is the source of their run-out. The chuck type tap holders that used to be made by Eclipse (James Neill) and Moore and Wright in the UK have a cheaper construction where the body of the holder itself is split to form a collet. This limits the size range of each holder and I don't feel they grip the square on the tap quite as firmly as the Starrett type, but it does eliminate the run-out you illustrated so well. Another point is that some taps don't have a centre hole or a cone at the square end. (I guess you could modify these by hard turning or grinding your own cone on them.) Thanks for the advanced insights and tips that no-one else has seemed to come up with.
I was going to say (before Joe kind of pointed it out) that the concentricity error is not (necessarily) in the centre at the end of the T-handle but where the chuck holds the tap. I've got some beautifully made (looks wise) chucking T-handle chucks and literally nothing is concentric with anything....so at least Starrett get more points than those!
Lol, idk why...but Jackie Gleeson kept coming to mind in Smokey and the Bandit. "You can think about it...but don't do it...." 😂
And my learning continues. Never even thought about it before. Thx Joe!
I'm glad others are learning this. I have tried to explain this to others, and without real time to explain in the shop atmosphere do to production it was difficult. It's amazing how some tools aren't applied correctly. Thanks to Joe Pie it's now out in the world.
I learned this the hard way messing up on a part. Also a tapping block is a good thing to make to get the tap started.
Totally agree, but lots of my taps don't have a conical point or a conical centre. I suppose I could grind a male centre on the end though. I've always blamed the split jaws on the tee tap handles. They are rarely the same dimension as the square on the end of the tap, so they pinch just on one end or the other.
Regards, Preso
Agree 100% Mark 👍
Robert
I discovered that an ordinary but high-quality drill chuck holding the tap hand-tightened. Drill the hole, then switch out the drill for the tap in the chuck, then tighten the tap by hand. Spin it up, and when the tap binds in the hole, it's dead center. Loosen the chuck, and it can be finished by hand with a t-handle. It works 100%.
Just put the tap in the tail stock chuck, close the jaws so that they are not tight enough to stop the tap rotating, and use your handle. I've been doing it that way for over 50 years. I don't break taps.
Once the tap is in the tailstock chuck, the square end is inaccessible. How do you drive it?
@@joepie221 You grip the shank or the end of the thread ( at the square end ) with the same screw on handle. I use a small 2 piece tap wrench that does the same job. On taps over 6mm/1/4" I grind a flat on the shank, because the handle/wrench tends to slip on that smooth shank, because of the torque required. So you only have as much shank as necessary for accuracy in the chuck jaws.
Make my own miniature tap wrenches, and they tighten with 2 Allen screws. They grip REALLY tightly.
THANK YOU! After getting away with this for many years, you have shown me the light and the error of my ways. I had no idea that there was a second end on the spring loaded tap guide.
The hole at the back is not the main problem - the two jaws holding the tap and the cone squeezing the jaws together are. There is no mechanism in the design of this type of tap holder to align the jaws to the axis of the holder. The holder is designed to be held by rather flexible “clamp” (human hand) that compensates for the misalignment. Machine tools do not have that flexibility and hence the problem.
Agreed
Thanks for this video. I could see myself going crazy if I'd scrapped my work from it.
It removes a great deal of the risk.
Thank you Joe. Sometimes a demonstration proves a point. I will stop the practice that you just condemned! I am a new believer.
Excellent tip, I never knew that a T-handle would have so much runout. I also never knew that those tap followers had a concave end on them, I'll have to tear mine apart and see. Thanks, Joe.
Nothing beats a good visual demo - point well made Joe!! :)
Brilliant demo. 👍
Joe this was a great example of how you don't realize how you can build tolerance into a part and think your doing a good job, seeing is believing.
Joe ~ I've been tapping a lot of small holes in expensive stainless parts. I can't count how many taps I've been breaking off in blind holes, ruining the parts. I've been using taps a couple sizes larger than the 75% thread recommendation to get around the problem, but it's still pretty scary. The info you shared I'm betting is 100% of my problem! I'll check it out today in the shop but this was a terrific bit of information! Thanks.
Excellent. Good luck. Another gem is not to over power the tap with a giant drive handle. The smaller the tap, the smaller the handle. You'll get much better feel.
I’ve noticed this same problem but I think it’s caused by the crappy jaws in the end of the tap handle. You can see the tap is held crooked in your close up. I have a very high quality tap handle that looks like it was made by Albrecht and it doesn’t have this problem
I can’t tell you how many times I pulled out a tap to use with that spring loaded tap guide only to find that it was pointy on the back end with no center hole and I had to tap freehand. I had no idea the end of the guide was reversible 🤦🏻♂️! I feel like such a doofus! 😂
No one who has learned something new is a doofus. A doofus is the person who watches this and keeps using the T-handle because they don't believe the facts in front of their eyes.
Well, I won't be doing that again. Thanks, Joe..
tour expertise is excellent. My practise is now changed thanks to Joe P
We’ll shit! Every time I come back to this channel I leave what I know at the door. Thanks so much for pointing this out. I’ll be sharing this with a few friends.
I tap most holes by clamping the tap in my Jacobs chuck. Tap only deep enough for good alignment then finish by hand. Yes I know you’re not supposed to do it that way but it’s worked for me for fifty years. Super Chucks are best for this since they grip tighter.
Good stuff, Joe! Found this out the hard way years ago. Basically used the same methods you demonstrated to discover the runout of the different drivers. Thanks for your time and sharing! 👍😎✌️
Excelent tip, ur right, hours spent making a little piece and suddenly a tap snaps..... Greetings from Mexico
That is cool. Your set up bypasses all the tolerance stack up compared to the "normal" set up. It's funny how in machining you
can have process issues that you just kind of put up with for years, then someone shows you a fix and it's so simple!
I think we get stuck in our ways. That is going in my bag of tricks, thanks!
You can buy better machined T tap style wrenches that are made specifically for doing what you just done. Tbh it depends on the application, hand tap, machine t tap, machine tap holder, machine tap joes method that just elimenates problems, or depending on the quality and class of thread macine cut the thread. As long as you know the quality of your work and the quality required you can then apply it to the task.
My t handle tap wrench has about a thou of runout with the indicator on he tap. His t-handle is junk. Better advice: Keep junk tools out of your shop.
@@gregoryhouck5738 to be fair, he highlighted a potential issue in your own quality control, and he got to make a wee video in doing so. Im all in favour of openess of knowlede and skills for all.
Even a good quality tap handle can have this problem. It all has to do with the short length of engagement of the tap end and the one sided closure design of the handle jaws. The handle used here was made in the USA and is superior quality to most handles its size.
Yup, All you forgot is to add "patience". Are we all not Patient, LOL.
Brilliant. Something new every time.
I stopped using those spring-loaded guides altogether because I could never get the tap to go in straight. I'd assumed that I - an untrained amateur - was just doing it incorrectly. I think that I'll give it a try again without the tap handle.
Hi Joe I use only spiral flute taps and hold these in the tailstock chuck. Don't lock the tailstock and present the tap to the workpiece. Select the lowest speed. While holding the jog button, pull the tailstock into workpiece until the tap is fully engaged. The tap will pull itself into the job. After the final depth is reached just reverse the chuck. Apply a small pull-out force to the tailstock before the tap emmerges. Cheers
Bravo Joe PIe, always spot on information, cheers from Florida, Paul
You are so full of it Joe.
"It" being valuable information learned over a lifetime of experience. Thank you very much for taking the time and putting in the effort to share such knowledge with the rest of us. I truly appreciate it!
I made a couple of these tapholders inspired from Your old video - they work great!
For very small taps I use a shopmade contraption with a small chuck on a 150mm handle with a precise center.
Dia is 15mm with knurling, works nicely for small stuff since it is possible to feel the small torque before messing up...
It's almost as though they made tap follower reversible on purpose.
Good lesson tonight Joe. I'm guilty as charged in doing it the wrong way but no more .Tomorrow I make a new small T handle and a small spring loaded follower.
Good advice as always Joe......
Tap wrenches vary quite a bit..... I have a little "Eclipse" one that I have owned for over 50 years and it runs true to less than .002", but the others I have are not that accurate. I must make a tap follower..... I often use a tailstock centre to start a tap, turning by hand and keeping the pressure on with the hand wheel at the same time. It works, but needs care, so a decent tap follower is on my 'to do' list... 🙂
Good little pointer , thanks for sharing some of your well known experiences!
My pleasure!
I learned something else I didn't know I needed to know. Thanks! My cheap Chinese T handle tap holders are almost unusable anyway.
Excellent demonstration Joe.
😳oh man! Newbie here and I just learned something new.... Will never do that again!! Thank you!
Get yourself a decent T handle wrench and its not a problem. If the center in the back WAS used to manufacture the device then it will run concentric. Your tap is not square in the jaws. I'm not some 'Fred in a shed' been making aerospace components for over 50 years!!!
You are correct, garbage t handle with jaws not broached on center. I bought some Starrett t handles about 20 years ago and one was unusable because of the jaws. I don't buy Starrett anymore.
The square jaws of the T handle are only parallel at one opening size. Any larger or smaller it can’t hold a tap coaxial with the hole, no matter how much you paid for it.
Joe Pie, never disappoints, or fails to educate!! Kudos Joe!!
Thanks Joe. Model Engineer from Australia
I always put the tap in the jacobs chuck and turn the lathe by hand to start a thread. Just a rookie here.
If I keep on watching, you I might turn into a sort of machinist given enough time. Thanks for the video keep on keeping on.
Hi Harold. I always appreciate when you take the time to visit my channel. Thank you sir. Stay well.
Up till now I didn't realize the pointy bit on the back of the tap was a concentric centre. An outie instead of an innie. Thank you!
Hey Joe, Thanks for all your videos. I've learned a lot from you and a few other TH-camrs. Actually, I am not a machinest. My degree is in Electronics Engineering Technology. But, I used to love spending as much time in the machine shop as posible, before retirement on disability in 2007. I just turned 74 and am now working in my little shop doing busy work. I can now fix, repiar, build and design most anything that the community brings into my shop. Moreover, i dont charge for any services. You have been a blessing to me over these years and i thank you sir, for all you have done for me and others.
Thank you very much for taking the time to leave such a great comment. This type of feedback really means a lot to me. Best of luck to you and be careful. BTW...My Father was an electronic engineer. He founded Artisan Controls Corp up in NJ. The company is still going strong today. Stay well.
Awesome bud. Disabled retired like yourself. We fix,make or repair everything. Where would mankind be without machinists.
@TomokosEnterprize Thank you for the comment Brother. I have many maladies, but the one that bothers me most is that I shake so badly that I can hardly hold my calipers to make a measurement, but with perseverance I somehow prevail, lol. I had a good friend years ago, who was a mechanical engineer. He and I worked together on several projects, me doing the electronics control and he doing the mechanical aspects. Joe Pie has several attributes that remind me of him.
@@Philippians4vs4-8 Hi, I have the same old man shaky hands that for me can be a really painful situation as I have found Pouring pure silver to save me from a Mindless atack of 2200F molten Silver. I found doing this highly intense thing to do after losing my wife due to cancer 10 years ago now. Stop by my site if you like. People like us need/despratly need to make things, Repair things and make them better if we can. It is all we ever known. WE have that in us to our last breath. My biggest wory is for the new generation coming to work have the need to do this. We can train a monky to pull the trigger to weld but it can't fabricate. I can't navigate Facebook but I can build an oil rig, LOL.
Great video. I made a spring loaded tap center years ago from stainless and bronze. I didn’t know you could get these with a variety of springs and two different ends. Mine is crude but it works and I have had it for many years. The T handle guides were awkward and wobbly. I used the T-Handle on small taps cuz the handle had the hole. I broke my share of taps until I figured this out the hard way.
In almost all most cases, misalignment like the one shown here is caused by the tip of the tap follower coming to a sharp point allowing the point to contact the bottom of tap wrench center, which prevents the female 60 degree taper on the tap wrench from contacting the male 60 degree taper on the tap follower. If you have a tap follower with a sharp point, grind enough of the point down to prevent it from making contact leading to misalignment problems. Very few if any tap wrenches are center drilled off center enough to affect alignment.
Good demonstration. I made your small tap handle after watching your build video. It’s excellent. My pump centre only has a point. I need to make a double ended tip like yours has.
Very good info,Joe.thank you.
Well explained and visualized. Thanks Joe
I really appreciate all you do and share, thank you so much Joe, Paul in Orlando
As always thank goodness you are there to guide us
Great tip Joe, thank you!
OK, convinced!
Amazing! Thanks Joe, I never would have thought that.
Great video, tip, & how-to, thanks Joe!
Thank you again for your simple and extremely useful tips!!
A picture is worth a thousand words. Beautifully presented. Thank you!
I always learn something useful from your videos...thanks.
Great lesson Joe!
I learned something today! thanks Joe.
You got me. I have been using a tap handle like that and did not realize it was doing that. Thanks for showing me this.
Great tips as ever, Joe you are a master of showing us those things that we just about did know, but not quite.
Thank-you! Great information I didn't know. And you have a gift for explaining AND demonstrating the point. God bless you. Your (and all) great gifts are indeed from the Lord.
Agree, well done presentation.
Learned this the hard way using the ratcheting tap handle from horror freight.
I certainly hope you don't use their taps too.
The taps are good for removing dings or rust from an existing thread, but not for cutting one from scratch.
As always, a great, informative video. Thanks.