Parting on the Lathe
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- เผยแพร่เมื่อ 6 ธ.ค. 2013
- Parting is one of the most misunderstood machining operations on the lathe. This video covers how to properly grind the tool, how to set the tool so it is rigid and properly aligned, and lubrication. Following these basic guidelines can greatly reduce the amount of heartburn associated with the parting operation.
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One handy tip I was taught at Tech. college about 50 years ago was to set the tool height using a small diameter ground rod held in the chuck and then trap a 6 inch steel rule between the tool and the rod. If the tool isn't spot on for height the rule won't be vertical (viewed from the tailstock end) and from the way it's leaning it's easy to see whether it's high or low.
Looked at lots of these instructions over the years and this is the best and complete parting video I've seen
Hey Tom,
Thank You Sir!! This video is going on 6 years old and its just as relevant today as it was the day you made it. NO distracting music! Thank you for you that! You spoke in a clear voice that even my deaf ears could understand perfectly. You didn't use a lot of Big Fancy $10 words, you spelled everything out in plain simple english that even a nimrod such as myself could easily follow. Looking for more of your video's as soon as I post my reply. Again, Thank You Sir!!!
JohnArcher
Thanks John
I saw this video several years ago, had problems parting, came back to watch this video -> found the solution to my problem
Excellent tutorial! I acquired my first lathe, a dirty old sheldon 11, and ordered a hss parting tool. I realized this is a controversial topic but now I'm sure doing it the right way should succeed!
I have the same exact Hardinge lathe. It has seriously prejudiced me against other engine lathes... so awesome to see another guy using that awesome machine.
I would have to agree, although my opinion is somewhat prejudiced. :)
Hi Tom,
Very nice video. I'm sure there are a bunch of folks that will breathe easier and be more confident parting in the lathe.
All the best,
Tom
Thanks Tom.
I don't know if you ever breathe easy while parting, but hopefully this will increase the confidence level a bit.
Tom
Nice instructive video - as always -thx !
The grinding ... I like to grind mine with a little "twist" so the parted off peace loosens before the center is reached on the left part - that's even better, I think, if there is a hole bored - no burr is left on the parted off peace ... on the other hand ... maybe I'm wrong ?
Keld Sørensen A hole through the center always helps, but be careful with the angled blade. That will cause the blade to creep sideways and bind. You can get away with it on small parts with little overhang, but larger parts will be a problem.
Tom
Tom's Techniques Yeah, ONLY small part with holes, you'r just right.
@@TomsTechniques Used to part off tiny brass parts at 1600rpm with the auto feed engaged. Parting tool always set on center, parallel to the travel with the correct inserts for the application. Even though it worked flawlessly again and again I was always holding my breath for this part...
I damaged 4 parting tool tips yesterday afternoon..... I wish I had come across this vid earlier! I see all my mistakes now. Great vid. Thanks.
Watching this after breaking my parting tool today and realizing I blanked on having a sharp tool. Add that to my mistake of not using a cutting fluid and viola! Broken tool. Thanks for the much needed knowledge!
Awesome video Tom. Thank you for making it. I spent a good 2 hours today fighting with 2 different HSS parting tools, because as it turns out, I had them slightly below centre. I thought that's where they needed to be located, until I saw your video! =) Confidence has been rebuilt. Thank you Tom!
Thank you for your info! I have been trying parting for 10 years and it never worked well. I did exactly what you showed, twice and the cut parts came out PERFECT!! Thank you so much! This video will now help me so much in all the years to come! Thank you!!
That's good to hear. The set-up for parting is pretty critical and there is a lot of things that need to be right for it to be successful. Glad it worked out for you.
Tom
You are awesome ! Went to
School along time ago for auto mechanics and still do that . Always wanted to do machine work too . Finally got
A mill , Lathe and other metal tools so these vids are great !
My one-to-go video when it comes to parting. Clarifies and pretty much sorts out the frustration in the most comforting way possible.
Parting can still be scary, but less so with a bit of knowledge.
I watched several videos on parting. Some are just awful. This is good video, good audio, clear instructions. Thanks for making a good one!
+Brian Meyette
Thanks for watching.
Best video on how to setup and use a parting blade, that I have found. Thanks 😀👍
Hi Tom, thanks for this - did my apprenticeship a few years ago now and haven't done any turning since, these videos are a great help :)
Ive never had much success parting, this video is great, clear and precise, I will try again now ive watched this, many thanks .
Thanks Tom, I've just bought a lathe & that was awesome
Excellent demonstration on parting
Thanks for the great video. I'm new to basic machining and your videos have helped me at my job making simple tooling in our small machine shop with old conventional machines. Keep up the great work. Thanks again.
Thanks for watching, John.
Good on you mate. Just solved my problems. I have a round bed Drummond lathe and I think the ridgidity and the speed are my main issues. Thanks
Thank you so much for this video! parting has been the bain of my life and was easily fixed thanks to this quick lesson I was one of those individuals grinding that hook on the end After changing the tip profile it worked perfect!
Thanks Again!!!
Pretty much reminded me of what I should have done in the first place as I have my compound rest hanging out about 3”. Pulled it back in over the cross slide and BOOM cut 4 pieces without issue as compared to the first one that popped the tool out of the holder.
hi all,,,, newbi here,, just thinking of getting a small clarks mini lathe, tom has been a fantastic help ,thanks again
thanks Tom, i had no luck before i watched your video, but now have managed to part off without breakage! very pleased
Good to hear!
Thanks for watching.
Thank you, Tom. After watching your video, I was able to see what i was doing wrong with my set up. I used your tips and got the parting tool to work correctly. Much appreciated!!
Good to hear!
Thanks ! I recently broke my boss’s cutoff tool....I missed a step,or two in my procedure..lol...but, it’s been 30 years since I needed to use one ! Great video...much appreciated !
Very nicely presented! When I had a Boxford, I milled a flat area at the back of the cross-slide and made a rear toolpost. Combined with flood coolant I could part off with confidence. When I got my Harrison L5, I was for a while parting off under power with an HSS blade holder in a Dickson QC. Then I went through a whole load of shattered blades and ruined parts and almost gave up parting off. Now I have a Dorrian BXA toolpost and use an inserted blade holder mounted upside down so the swarf falls out of the cut. It also allows you to easily see the finish in cut, so you can spot any problems, a chipped edge, or buildup etc. and do something about it before a disaster. I keep my topslide gibs very tight for rigidity which helps a lot. I can always slack them off if I have to get a smooth finish on a short taper.
Good tips Paul!
Thanks for watching.
Tom
Awesome! I just recently had to part a piece, now with this video I know how to improve on quite a few aspects of my work!!! Thank you!!!
Thanks for watching
Thanks for creating such a resource for those of us that are getting interested in machining. Such a value and time saver, not to mention mistake prevention.
Just learned the definition of viewer appreciation.
It's good to hear that my efforts are appreciated. Thanks for watching.
Tom
Thanks Tom...for all your videos!
You are welcome. I'm just processing another one now that should be up later tonight.
Tom
When I was an apprentice scientific instrument maker, I was taught to never stand in front of a grinding wheel when it was running up to speed, because as it was running up it would pass through resonance frequencies related to any slight imbalance there might be in the wheel, and that is when the wheel could shatter. A grinding wheel shattering in your face could be horribly injurious and possibly fatal. I have enormous respect for your skills, so it was something of a surprise to me that you stood in front of the wheel when starting it.
That is a good rule to follow, but it is more applicable to a newly mounted wheel on a surface grinder, than one that has been in service on a bench grinder. Surface grinder wheels are much more friable than those used on a bench grinder and, since they are often removed and replaced, are much more susceptible to damage. It never hurts to stand to the side of any wheel, but the chances of a wheel failing on a regularly used bench grinder are slim to none.
Tom, this was a great video. I've been planning my shop and machines for a very long time, read and watched a bunch. Tonight with my wife watching, I did the first lathe work of my life (and enjoyed it so immensely it must not be legal!). My huge project was to take some 7/8" aluminum round stock, cut off a chunk, true it out, face it, cut through the dull finish, knurl it, chamfer the edge and then part it out. Everything went like clockwork until parting it out - then I realized I have not been paying enough attention to these details! In the end, I parted it with a vice and a hacksaw, and my wife fell asleep before I could drill and press an existing cap-head screw to turn it into an easy access knob to the gear housing. So 80% there. But along the way, I noticed a pile of things I need to address in my process and tool prep. You have a new subscriber! Grazie!!
It's always great to hear from an enthusiastic novice. Parting is one of the most difficult machining processes, so don't get discouraged. Once you learn the ins and outs of your particular lathe, it will get easier.
Have fun!
Tom
Great video. Thanks for posting.
Hi Tom,
Thank you for another helpful video. The new tool post made a big difference over the lantern type.
George
Thanks for watching George. You got a new tool post already?
Tom
Thank you for a very informative video, this will be of great help.
Nice, simple to understand video on parting. One of the things I've learned as a beginner/hobby was also understanding that similar to limiting the overhang of the tool is the overhang of the work piece being parted off, especially on smaller pieces.
Yes, minimum overhang should be considered for everything from the tool to the work, even the compound.
Brilliant videos. Yours are without a doubt the best on TH-cam
+Jon Carter
Thanks! It's good to know they are appreciated.
Tom
Thank you very much for this, just tried your method and it worked flawlessly.
Excellent. Thanks for watching!
Tom
Oh man, is that Hardinge lathe a beauty; we have an old one here, used and abused for years, and it's still like a top!
They run forever.
My funniest experience parting was in the Navy. On my ship there were life jacket cabinets all down the side of the decks with brass knurled knobs that held them closed. The guys would take those knobs and throw them at sea gulls so I was continuously making new ones ( several buckets full per week.)
And THAT'S ! WHY ! YOU ! WERE ! DISCHARGED !!!
Thanks Tom! Half the time, I’ve been staring with the parting tool and finishing with a hack saw because my tool always grabbed and broke etc. I’ll try it again your way!
Nothing wrong with finishing up with a saw. I've bandsawed larger pieces myself after reaching as far as I could with the parting tool.
Thanks for the great guide on how to do the cutting.
You are very welcome
Great thanks - I'm new at metal turning - this taught me plenty
Very helpful. Thank you for your sharing.
Excellent,great video thanks
Great video, I'm really enjoying the beginners guides, learning lots. One thing I do in addition is lock the carriage once i'm ready to part off. Really helps on my lathe with rigidity.
That's a good tip. Thanks for sharing it.
Tom
4:20 "If you're using a lantern-type toolpost... good luck. They're not known for their rigidity, and your chances of successfully parting are GREATLY REDUCED using a lantern-type or rocker-type toolpost."
Truer words were never spoken! Last weekend I needed to make a gib screw for my '42 SB 10R, and used a 1-1/4x4" bolt for stock. I decided to part the head off... there's an hour I'll never get back. I should have used a hacksaw, I'd have been done sooner! 😂
Next payday: a parting tool holder for my turret toolpost...
This is a great video. Thanks for the information. Something you should show is how to center the cutter using the “ pinched 6 scale” method for when you don’t have the luxury of getting up close to the end of your work.😊
Excellent video
Thanks Tom! I purchased a 10-22 Precicision Matthews lathe a little while ago and have been trying to figure out this parting operation. Your tips were very useful. I need less speed, more oil and to make sure the cutter is straight. Scared the crap out of myself a couple times when the cutter bound up. Yikes!
+6milesup
Yup, that really gets your attention. Glad the video helped.
Tom
Thanks Tom, nice video. On my china lathe i learned that when i move the compund to almost parallel to the cross slide and move the compound far back I get much better regidity.
Lars,
Whatever it takes to reduce overhang will help. It's great that you experiment with your machine because they are all different.
Tom
Good method.. I do the same
I will have to consider doing this type of cutting from now on. Thank you. Peace :)
nice video Tom,you explained it very well thank you................
+Ray Falcone
Thanks for watching, Ray.
Good work dear sir
Thank you, that was very helpful 👍
Thanks, never thought to use a dial indicator for perpendicularity for a cut off tool.
Thanks for the great video!
excellent video
This was very helpful. THANKS!
Thanks for watching
Thanks for the help. Very informative!
Happy to offer it.
Great video Tom
Thanks Cliff.
Thanks for the clear instructions.
Thanks for watching
Another good video on a sometimes tricky subject. I had a small cheap parting tool made for a mini-lathe that had a thin T-blade as you show, but it did not hold the blade very well. It worked OK on Delrin but when I tried it on steel it seemed to grab and jump as I tried to keep a steady feed. What was actually happening was the blade was being pushed back into the holder, and as I neared the center the holder hit the work and snapped.
I also have a cheap carbide tipped tool from HF that I touched up with a diamond file and it worked OK on mild steel, but it did not seem to want to work on a galvanized steel pipe fitting (probably more like cast iron). But it's also tricky to part pipe, as the bore may not be exactly concentric and the tool will catch where it cuts through. I used a hacksaw and then faced it on the lathe.
Thanks for the tips. BTW, I think it is better to err on having the tool below center, as the rotation will push the tool tip down and away from the work. If it's above, the downward motion will push the tip into the work and grab or chatter. YMMV..
For best results, the tool tip should on dead center, NEVER above or below. If it's above center, the tool will drag under the cutting edge and if it's below, it will pull in as you near then center of the part.
What causes chatter/vibration? I don't see it when I use the power feed!
I have used the squaring up against the chuck method and never thought to use the indicator to square it up,makes perfect sense.
The indicator takes a bit longer, but it ensures that the tool is dead square, which is the most important part of the set-up.
Tom
nice and clean ! good video !
Thanks for watching
Thanks for posting this
Very nice lesson
Good advice, I would just add one more thought. On my older South Bend 9 I find it helps alot if I snug up the gibs to ensure a tight setup with NO play. Usually just tighten up one screw on the cross slide and lock the carriage. Parting has always been a white knuckle adventure in my shop !!
Absolutely. I've done plenty of parting on South Bend lathes. Anything you can do to increase rigidity will help.
Thanks for watching.
Tom
Thanks for the vids Tom. Your tool sharpening video was super helpful. I have a lantern style tool post at the moment and have yet to successfully part steel. I have however successfully jammed my lathe lol.
Lantern tool posts lack the rigidity necessary for reliable parting. Plus, they tip the tool back, increasing the chance that the tool will grab the work.
Glad the video helped.
@@TomsTechniques yeah, that's become more evident the more I've tried it lol. For now it'll have to be the zipcut until I get a better tool post. Thanks again 👍😁👍.
Thank you man! Im making a coligraphy pen in my manufacturing class and it will have multiple parts. And I needed to learn how to part. Thank you! Just making sure, so when I part aluminum I run RPM at about half the RPM I would turn normally at?
savage man!! great content , learnt a lot, thanks for sharing
tom you have a very good lathe with a wonderfull 6 jaw chuck ,good video tom
Thanks you saved my time
Thanks big tom ,greatly appreciated
Big bad Tom. :)
Thanks for watching.
Thank you Tom.
Great job 👍👍👍👍
Awesome. Thanks for another great video. And yes it actually was a big mystery until now as it's one thing that I have and I haven't bothered using it because I didn't know anything about it. Looks pretty easy now.
Don't get over confident. Parting is one of those operations that will jump up and bite you when least expected.
Tom
Tom's Techniques
Oh great. LOL. I'll be careful when I try it and make sure the safety glasses are on. Thanks for the warning.
nice and clean , good job
+wael alabrouni
Thanks for watching.
thanx for this video buddy. it was very informational.
Thanks for watching
Hello Tom, Check, check, check, and check. Do all those things on my 12x36 Grizzly G4000G. I have used 'T' blades, beveled blades, carbide inserts of all kinds on my QCTP. Dead center and within a molecule of square. Been playing with it for more than ten years of home shopping and eight out of ten times it seems to go well almost always when I am parting a tube or hole in the center workpiece. When it comes to parting of solid stock the tool(s) seems to do very well until they get to the small diameter and then the tool pressure increases dramatically and comes to a stall. If I power feed same thing. I have shattered carbide, destroyed blade holders in parting tools, broken grooving bits and holders, pushed HSS blades back even with the wedge holder clamped very very securely. I use lots (steady drip) of cutting fluid to no avail. The last time this happened I was parting a two and a half inch solid aluminum rod!!! Broke the insert and tool holder as well as rotated the QCTP (yes it was cranked down). The only thing I haven't tried with my track record I am reluctant to boost rpm above the six hundred mark as things happen pretty quickly at those rpms. I have tried everything from 600 rpm on down though. Any thoughts on why the tool pressure elevates so much as it approaches center? I am totally stumped. I get success enough to keep trying but these crashes are making me gun shy for sure. I have sharpened and honed both the HSS and the carbide (honed). Present practice has me grooving the piece and finishing on the bandsaw. I have watched countless videos and tutorials without seeing a solution. Needless to say this is a very good subject and thanks for the video. Take care. Doug
Two things will cause the resistance to increase as the tool approaches center, either the tool is set too high, or there is increased friction on the sides of the tool. You mention using cutting fluid. I prefer a good old fashioned sulfur based cutting oil for parting. That may help with the latter.
Tom
Thank you. Very helpful to a beginner like myself 👍🏽
Good to hear!
Man, that is one sweeeet lathe you have.
It's my baby. I bought it new in the early 80's.
This is super helpful thank you!
+Method of Kolishin
Hope it helps
thank you for that video, very informative
This is super helpful
Excellent commentary.
Thanks for watching
Another note about chip breakers and a reason why I don’t like them: I find they increase the tendency for the tool to get sucked in, and in deep grooves they can, in my experience, cause chip evacuation problems. The chips end up curling up on top of the tool like green onions, then binding up instead of getting out of the way like the would on a flat topped tool
I'm just starting to work on a lathe and I noticed that as well. It almost feels like the angle causes the tool to want to "slide down the ramp" it makes but that could just be my inexperience and inconsistent feed rate
@@Trenz0 if you’ve got chip breakers try grinding them less aggressively. I’ve found that longer/shallower chip breakers cause me fewer problems
Great video, thank you!
+Marko Palikko
Thanks. Glad you liked it.
Tom
Excellent job, T/Y.
Great video Tom 😁
Thanks for watching!
Hi Tom, this was well presented. Alot of my machinist buddies are afraid of parting tools. But as you said - if you're set up right, there shouldn't be a problem. I just recently purchased an Iscar blade and block type parting tool that uses carbide inserts. I have parted off 4" diameter 6061 aluminum using a 5/32" wide blade many times with no problems. Of course if there's enough material I would normally tell my students to use the cutoff saw. But they sometimes get themselves boxed into a corner and I part the bigger stuff off for them so they don't break my expensive tool. Thanks.
Ujeb08
Thanks.
On larger parts, I'll sometimes part them off part way through and finish up with the saw. That gives you a guide for the saw and saves a bit of time.
Tom
Great vid! I wish I would have had one like this a couple of years ago.....before I did all my "practice" with an expensive insert style holder. LOL ......the one that I've had to replace. I think I'll be giving the HSS cutters another chance! :)
Mike
Thanks Mike, I'm glad you enjoyed it.
I'm not a big fan of carbide inserts in the home shop in general. HSS is more forgiving, inexpensive, and much more flexible than carbide inserts.
Tom
Fantastic
A huge thank you!!!
Thank you so much sir.
Thank you so much ! I'm off to buy a quick change tool holder !
GREAT FUNDAMENTALS.
+GARRY BASHAM
Thanks
Great video on how to cut off parts on a lathe
Thanks, I'm glad you enjoyed it.
Tom
I use a mini lathe and this what has given me the most problems. One of the things I found was that i needed to re- adjust the cross slide as there was some up\down movement. that led to re-setting all the gibs as well. Only just done this not had a chance to see if this improves my cutting off. One thing you didn't mention was to lock the carriage to the bed.
part off close to the chuck , and use the variable speed if you have it , so your rpms are increased as you approach the center thus keeping the fpm the same
also, on the mini lathes its tough to have a smooth feeding compound and a rigid tool rest all in one.. I always use to overtighten the center gib screw just a 1/4 turn for parting , then back it out after for normal use.
Great tip on the gib screw, these mini lathes are just not rigid enough out of the box, I've snapped a parting off tool, it's not a T profile one though, will look for those next time.
Steve Clark yes, when parting i have to say my bigger machine , although not huge ( grizzly g4000) is a lot more forgiving .. I can screw up and not always snap a blade or crash the work.. i still use the gib screw trick though above 1 inch diameter aluminum