The Ultimate Trick: Cutting off with the Mini Lathe
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- เผยแพร่เมื่อ 27 ต.ค. 2014
- Parting on a small hobby lathe is difficult, because of the lack of rigidity on a small lathe. This video shows a solution.
This solution also prevents chatter when making deep cuts with form tools.
For a general introduction to parting and everything else that has to do with metal work please look at the videos of my TH-cam teachers mrpete222, Toms Techniques and oxtoolco.
The tool in the simulation is not on center height. I noticed this error after I uploaded the video. I forgot to set it at center for the presentation, after I simulalted it at center height, below center height and above center height. Reverse operation did always work better in the simulated flexible lathe. I do not claim that inversion of the cutting tool generally improves efficiency. But it improves heavy cuts on non rigid hobby lathes. If you only work with big, heavy, rigid professional lathes you may never have had problems with cutting off. - วิทยาศาสตร์และเทคโนโลยี
I really cracked up when you said "that's a cloud going by"! Laughed my socks off - brilliant!
8-)
Thanks for the excellent suggestion Latheman, I just tried this on my 7x16 Mini Lathe which has a forward/reverse switch and I was able to part a 20mm dia bar of aluminum for the first time ever!
This note is for the doom and gloom merchants: The carriage didn't fly off killing a nearby fluffy white kitten, mainly because it can't, being totally captive to the bed, and the chuck didn't unscrew and race across the floor smashing into my wooden crate full of jars of nitroglycerine, because on my mini lathe the chuck is bolted to the spindle, it doesn't unscrew.
I suspect that Latheman knew all this about the Mini Lathe when he made this video titled 'Cutting off with the Mini Lathe'.
Cheers
In the golden age of British model engineering (between the two world wars) a common modification to a lathe was a "rear tool post" on the cross slide.
It exploited the same cutting geometry your video shows (the rear of the workpiece is of course moving upwards). The rear tool post was normally fitted permanently with a parting tool.
This was also the days before QC toolposts, so not having to swap a parting tool into the main tool post was a double-win.
There are a few videos on youtube of present day rear tool posts used for parting off.
your computer simulation was amazing.
I saw this a couple of days ago and wondered out accurate it was. Today I was trying to part a 3/4" metal bar and kept having all kinds of problems and not getting my piece cut off. I decided to give you recommendation a trial run.
1) Had to invert the cutoff tool in the tool holder.
2) Had to recenter the cutoff tool in the quick change tool holder, had to go to the maximum of the adjustment to get it close.
3) Had to remember to reverse the lathe before starting the cutoff.
Very happy to say that it worked well for me. Did three cutoffs and finished up the project that I was working on.
I'm about to buy my first lathe and I think I just learned something many professionals wouldn't know, thank you, this is high quality content.
Good video. Inspired me to sort out my rear toolpost this evening and it just completely fixed all my parting off chatter. Good man!
You can also get the same or even better results by using a rear tool post and running forwards with the tool upside down. When I was an apprentice (many years ago) the reason for the increased rigidity was explained to me as being because the reaction on the spindle from the tool forces is directed vertically downwards into the spindle bearings where the weight of the spindle has already taken up any small clearance that there must be in order for the spindle to rotate. Wether this is true is debatable, however it should be noted that all capstan lathes have rear toolposts and upside down part offs.
Yeah it seems like there is a brotherhood of man--sharing information--talking to people you have never met and getting along like a house on fire...It really is a wonder of the 21st century and the information stream is huge..There is so much trouble in the world with extremism and we have youtube which by and large is the opposite--we all get along and we encourage each other....win win win..
Just ordered my first lathe and I was wondering about this. Always thinking it would be difficult to not break tooling. Glad I was fortunate enough to stumble across your video. Probably just saved me countless hours of frustration. Thanks for a great video.
I learned something new on youtube today. I'll be running my next cutoff in reverse.
I had thought this method would work having seen rear tool post parting done. The best and most graphic demonstration of how effective this method works is when you used a profile (round) tool. the results speak for themselves. Cheers from John Australia.
Perhaps the best solution is to get a back-side parting tool post. Many people like these better because you can leave both your cutting tool and parting tool mounted at the same time. I have to remove my cutting tool to mount the front-side parting tool and even have to remove the work because it is in the way of replacing posts. My stepper motor mount prevents me from removing the T-Slot posts from the front side. Also, with a back-side parting tool post you get the benefits of a down-facing cutting edge (as you describe) without having to run the chuck backwards and risking it unscrewing itself. Having both parting and cutting tool posts mounted at the same time means a CNC-user can turn and part all in the same program without stopping.
You did this video 8 years ago but I have just washed it. It is very interesting and your way of talking and description is so much fun. And your idea here looks extremely useful i'm going to try the upside down approach. Much appreciated thank you
Thank you Latheman! I have always dreaded parting on my lathe. This tip works like a charm even with slower RPM and slow cross feed. Getting the tool height correct is important as with any lathe tool. I took my time and learned on scrap pieces. Works beautiful! Thanks !!!!!!!
Quality demonstration with good humour. Top stuff.
Thank you Latheman. This video provides very useful information, especially it provides a clear explanation and simulation for how it works.
Thank you for this tip, I have a C2 mini lathe and parting off has been all but impossible till now. Such a simple solution that never occurred to me. I can now part off quickly and cleanly without fear of the tool digging in. Thanks again and keep up the good work.
Thanks for the info man! Parting has had me in fits for a few days and your method I will try in the morning out in the shop! Have fun!
Gerry
Sense of humour appeals, nicely done.
Very useful and helpful info, thanks for sharing.
+Aaron DC mediA
zomg the cloud cracked me up. I think the deadpan narration is perfect.
Just happened across your video. I went and tried this on my mini lathe and it worked great. Thanks.
thank you for posting this very helpful tip for parting off work in mini lathes. This will be put into action on my lathes as from now.
Awesome method thanks, I have never thought of this. I will be using this from now on. A huge thumbs up for you.
Great use of humor and your videos keep up the good work.
Great video, and the clouds deserve their own thumbs up as well.
Thank you,solved my parting off problems straight away.
"Happy little clouds; this is a feature that most "serious" simulations don't have- . classic
Very interesting. The simulation made it more clear. I'll have to try it because it is such a pain to part with my mini-lathe.
Well done, that was a very practical explanation of what happens. I don't have a machine but have considered it. It's nice to know this information. Thank you.
I also like the fact that it sheds the chips downward. Great idea!
Thanks. The simulation with the spring models was the best part.
Shannon Price Glad you enjoyed it. Thanks!
+Latheman666 I dont like the simulation because you did not change the tool height when you ran the lathe in normal cutting direction. That way the tool was much more offcenter than in the reverse scenario and that causes the difference.
I have a c2 mini lathe with a hss mini cutoff tool from ebay and using aluminium I found for getting a good cuttoff you need your tool height on centerline and feed consistent so your tool doesnt rub on the workpiece.
Very well explained, now I know, thank you. I will watch more of your videos but I'm sure it won't be a waste of time, thanks again.
I tried parting in reverse and it works well, thanks for the tip!
Thank you for the video. Among the benchtop lathes, which do you recommend?
Thanks for this tip. I am going to buy a mini lathe so this will certainly help.
parting in a mini lathe, I thought it was not possible. What kind of magic is this?!? After pulling out my hair and eventually giving up on parting, I will seriousy give this a try!!!!
I just found this video and it solved a problem I have lived with for years! Previously I resorted to a bar clamp between the bottom of the saddle and the slide holding the tool holder tightening it only enuf to stabilize the tool but still allowing the cross feed slide to work. This was not the best solution. But the solution shown here is WONDERFUL! I tried it on a piece of scrap brass and the tool slid thru that brass like a hot knife thru butter! I use the quick-release tool holders and with the adjusting nut all the way down against the holder the holder is still not high enough to center the upside down tool. I will mill the top surface of the quick release holder down a bit to allow enough vertical adjustment to center the tool. I will paint the top of the tool holder RED to remind myself to run the spindle backwards. THANKS for the video!
I saw you video years ago and have been cutting off in reverse ever sense I saw you video. My mini lathe was new from the factory when I bought it. To date I haven’t had any problems with it like in the comments below. I have found also other thing That helped. Locking down your saddle so it would move when cutting. Thanks for sharing again
You are welcome. I'm glad I could help you.
Thanks - wonderful suggestion - really helped - I lost all hopes that I would ever do a reliable parting with Grizzly G0765 mini lathe in the normal way even after all fine adjustments - the very sight of tool digging underneath work was a horror to see - this trick came in handy - finally peace reigned
You are welcome. Glad I could help you.
Thank you for sharing, you are using the same technique that I was thought in technical school using a South Bend 9, it works and it is faster. We made our own cutting tools, and we did not have inserts. Thank you and have a good day, be safe.
Complete newb on the lathe here. Tried parting off first time today with Grizzly 7x14. Will definitely try this next time!
I used this method today on my mini lathe. Once the tool height was set properly, it worked on brass and small diameter steel like a knife through butter. No chatter or digging in and a smooth progressive cut Thanks for the video
It worked great on my mini lathe too thankyou very much for a much easier way to part off...
You're welcome.
Not only is this a great tip, and a great video, but this guys voice is cool as fuck. Sounds like Werner Herzog.
Very interesting, I never heard about cutting in reverse direction. I'll giving a try, thanks!
Amazing trick. Thanks for sharing 💪
Great demo. Thank you!
Totally brilliant, now why didn't I think of that? Thank you sir!
With regards to your simulation it’s shows the cutting tool at the same height in both directions. If you run your lathe in the conventional anticlockwise direction as you look at the chuck the tip of you cutter should be just below center then it wount pull the tool in like the simulation showed. This may be where you had problems in the first place.
Hope this helps
thank you for showing the technique.
Did'nt realize this vid is 9 years old but I did this today its the first time Ive parted without the hair on my neck standing up.Very useful Vidiso Thanks
Thanks i needed that .the biggest problem i have on my machine is parting.even with a large machine i break parting tools cutting wide diameter pieces. I hope this works cutting large stock
Very good! It is the way most cnc's cut . Does it work on steel??
"This is a cloud going by" - tremendous. :-)
Great tip. Thank you for sharing.
Unreal thank you so much!
Dear Latheman666: Thank you, thank you, thank you. You have really showed me a great trick to make it easier to work some difficult pieces on the mini lathe. And I really appreciate the explanation also. I have just subscribed to your channel!
+Angelo Zucco Thanks, I'm glad that I could help you.
Fun And Educational! Nice Job! Thanks!
really useful! how did not know this, thank you!
Thank you! I'm going to try this!!
For beginner machinist out there your "Phun" example is a good visual, well done
Thanks!
going to try this tonight, thanx
excellent!!!! 10/10 for you, thankyou.
Looks like a good tip will try
Nicely done!
Thanks, I will be trying this technique! I'd like to add, I read somewhere that cutting a small notch in the center of the HSS parting tool will help with chatter. I tried it myself, and it does seem to help to reduce chatter on a smaller lathe, in forward rotation. The notch was cut using a thin dremel cut off wheel. The groove runs parallel to the sides of the cutoff tool, making a small V shape in the top edge of the parting tool. It seems the shearing action of the V groove helps remove chips, and there's less surface touching the work. That said, I think your idea is better for larger forming tools.
very informative . thank you
I'll be trying this.
Neat trick, and well explained.
My last lathe was a 10x24 Jet which is a full function machine with right/left carriage feeds, in/out cross feeds, full gearbox and back gears. It was almost 700 pounds (317 kg); kind of a beast for its capacity. I knew nothing of rigidity problems with it. I sold it because of a long distance move and bought a sub-500 pound (226 kg) 11x26 which is closer to a mini-lathe in its construction. It has taught me the meaning of a less than rigid lathe. I'll certainly give this a try!
Neat idea! I'll try it too.
I have a diy 80mm chuck mini lathe with a small cross slide. I was unable to cut off aluminum part. But with that reverse cutting technique Im able to cut off 30mm steel with hss tool. Thank you...
Great video and concept
Interesting. The simulation with the cloud was priceless. What simulation software is that?
Another 10++, a Beaut for sure! Thxs!
that video was hilarious. I must subscribe now
brilliant, thank you, I give it a try....
Thanks sir, it work very well!!!
Thanks, good video helped me a lot.
Thank you, thank you and thank you one more time.
I`ll try this, thanks!
Thank you for this excellent trick. And the cloud
Bob Smith You are welcome.
great work, great tip and tricks. great info. thanks for sharing.
sam yeates I'm glad you liked it. Thanks!
no words ! thanks
I have been doing this wrong for 30 years. Thank you!!
THANK YOU
thanks that helps me a lot
Thanks!
thank you.
Thank you very very much
I would not do this on a taig mini lathe because the chuck will come off the threaded spindle, but when you use a cut off tool on the backside of the workpiece (with the tool upside down) you will achieve the exact same thing.
I have a 1936 atlas 10d and chuck will screw off if I run backwards and I don't have reverse anyway but it does a good job on cut off if I turn the tool up side down and feed from the back side sense the atlas d does not have power cross feed I made one with a windshield wiper motor and a pwm and it cuts of like a champ
Hi when I was apprentice in the late 50 's I worked on a BRM 150 Italian make lathe and it had a back tool post on the end of the crosslide for parting off upside down. The back tool post was mainly to have a parting tool always available. The front tool post was a QCTP type.
😎👍 nice job works great
the actual reason it works better is due to the spindle bearings in your headstock. excessive bearing clearance allows the spindle to lift and bounce causing chatter. never cut slow slow with an inserted tip these tips need speed friction and pressure to achieve a proper cut. if you want to run slow use high speed steel tools
Very interesting.
good video, thanks. This trick is known since a long time and works particularly well for mini lathes which all suffer from low rigidity. However there is a safety risk for lathes with a chuck mounted to a threaded main spindle. By reversing the spindle direction those chucks can work loose and jump in the face of the user. Such lathes should NEVER user reversed spindle directions.
brilliant, really useful information, il be using this on our lathe at work, that animation is a great tool (pun intended). Just as you cut through the final little bit of material you got an audible noise that sounded like it was colliding with tool can you confirm that the part was ok
+nathan hellyer I don't remember.
Just a small tip for a C2 lathe. If you have a standard parting tool holder you might get it to fit if you turn the standard toolpost upside down and use grub screws to hold the parting tool. This trick allowed me to mount my standard parting tool holder and get it on center to try out this process - it worked great, allowing me to part off a 3/4 dia brass rod with one smooth cut. I intend to make a custom toolpost to hold three sizes of parting tool so I can just drop it on and use the required size of tool.
Good tip: I have a Big Dog Lathe and lost a blade during a cut due to the lack of rigidity of the machine. Vielen Dank für diese einfache und rationelle Lösung.
This was very interesting need to c if I can get my lathe to run backwords
A friend on one of the engineering forums gave me a good explanation as to why latheman is correct that the parting blade is knocked clear of the work piece if a problem arises,,, he explained it kinda like this,,the blade is indeed pulled into the work piece when it jams while the machine is running forward but when the machine is in reverse any 'play' that exists in the toolpost holder and compound slide ect,will open out and allow the tool to be pushed clear,but in forward mode the same 'play' is compressed tighter by the force of the work piece pushing downward..thus everything jams up....at least I think thats what you guys are trying to explain to me...Ian,model engine making is a quite recent hobby of mine and where I live I don't have anyone else nearby who has the same hobby so utube has been a great source of info for me as it lets me see things actually being done which is always better than just reading 'how to' in a mag or on a forum..any new tasks I have to do I check utube first to see if someone has posted a video of themselves doing that particular job...its a really good resource for novices like myself..
There's more to it than that -- the geometry of the tool post drives this effect. Because the support for the tool isn't directly beneath it, cutting pressure exerts a bending/rotating force on the tool post and lathe bed. With the normal arrangement any such bending causes the tool to hog deeper into the work, but if you run the spindle the other way the bending force relieves the tool instead.