I had a 12" lathe that I bought brand new years ago, and I could never part off without chatter. One day I decided to check the preload on the tapered roller spindle bearings. They were not set tight enough from the factory. After adjusting the preload nut, the machine would part off like cutting through butter. What you said pretty well covers all the problems, but I thought I would add that one as well. Thanks from the USA. We love ya, buddy!
Same here! I’ve got a 9x20 lathe that nearly drove me crazy trying to stop the parting chatter! As a last resort, I tightened the bearings (they seemed fairly tight already!) and instantly the chatter stopped!
That would be awesome. Although I feel I have learned most already because of the clear expanations in all his videos already. “I do it like this because…” gets my ears pointed every time!
I used to dread parting off until I bought one of the parting tools you recommended. Now I find it easy. Auto feed and plenty of soluble cutting fluid or wd40 on aluminium.
John, I do very much the same as you do for parting off ops with one difference in that i gave up trying to get cutting lube into the deepening parting groove with a small brush. Instead of the brush I now use a small bellows type squeezy plastic bottle fitted with a canula type hypodermic syringe needle on the neck and filled with cutting oil. This bottle set up makes it real easy to get the cutting oil exactly where it needs to be throughout the whole cut.
Thanks for sharing your skill and knowledge. No matter how long a person does this I find that there is always something to be reminded of something new to be learned. I would like to add the the position of the cutting tool in relation to the forward edge of the cross slide should be as short as possible. So if the compound has the cutting tool extended in relation to the forward edge of the cross slide then retract the compound so the the cutting tool is as close to the edge of the cross slide. I have a HF mini lathe and this one thing has helped me to part off stock much easier. I have locked up the lathe when parting because the cutting blade deflected too much because the compound was extended too much. Again, thanks for sharing!
Can't agree more with regards to the compound slide. I replaced the very weak compound slide of my lightweight Emco Compact 8 lathe with a solid tool post.This solved all of my previous parting off issues. Mounting the parting tool upside down and running the lathe in reverse also helps in some cases. If you mount the tool in the regular way the cutting forces press the tool down and (on most lathes) towards the work. This increases the thickness of the chip which increases the forces... death spiral. In upside down mode the cutting edge is deflected away from the work.
Awesome. Regarding speeds is there any official calculation to work it out for Parting off. You mentioned 300 rpm even for carbide so I think I've been running mine too fast.
If you consider how fast the carbide tools are cutting on a CNC machine it gives you some idea what they are really capable of. The secret ingredient to successful parting at high spindle speeds and feeds is lots of coolant to evacuate the chips and prevent overheating.
I use the parting of tool upside down on the other side of the cross slide, This is how they were used on capstan lathes when I was an apprentice. The advantage is that it is on a single toolpost which is more ridgid than the compound and tool holder. The weight of the chuck adds to the cutting force so both force the work peice down onto the bed. A bonus is that it free's a tool position on my rotating tool holder.
I’d also suggest:- reduce chatter, lock ways on the main carriage & top slide. - that the cutting tool is wider at the cutting edge narrow to the back to reduce side friction. Check out “blondihacks”for lathe and milling basics instruction.
I had a 12" lathe that I bought brand new years ago, and I could never part off without chatter. One day I decided to check the preload on the tapered roller spindle bearings. They were not set tight enough from the factory. After adjusting the preload nut, the machine would part off like cutting through butter. What you said pretty well covers all the problems, but I thought I would add that one as well. Thanks from the USA. We love ya, buddy!
Same here! I’ve got a 9x20 lathe that nearly drove me crazy trying to stop the parting chatter! As a last resort, I tightened the bearings (they seemed fairly tight already!) and instantly the chatter stopped!
John can you do a milling machine tutorial after you finish the lathe series.?
That would be awesome. Although I feel I have learned most already because of the clear expanations in all his videos already. “I do it like this because…” gets my ears pointed every time!
I've been watching you piss about for about ten years now John. I've learned a good deal in that time.
Best wishes, Dean.
I used to dread parting off until I bought one of the parting tools you recommended. Now I find it easy. Auto feed and plenty of soluble cutting fluid or wd40 on aluminium.
John, I do very much the same as you do for parting off ops with one difference in that i gave up trying to get cutting lube into the deepening parting groove with a small brush.
Instead of the brush I now use a small bellows type squeezy plastic bottle fitted with a canula type hypodermic syringe needle on the neck and filled with cutting oil. This bottle set up makes it real easy to get the cutting oil exactly where it needs to be throughout the whole cut.
Thanks for sharing your skill and knowledge. No matter how long a person does this I find that there is always something to be reminded of something new to be learned. I would like to add the the position of the cutting tool in relation to the forward edge of the cross slide should be as short as possible. So if the compound has the cutting tool extended in relation to the forward edge of the cross slide then retract the compound so the the cutting tool is as close to the edge of the cross slide. I have a HF mini lathe and this one thing has helped me to part off stock much easier. I have locked up the lathe when parting because the cutting blade deflected too much because the compound was extended too much. Again, thanks for sharing!
Can't agree more with regards to the compound slide. I replaced the very weak compound slide of my lightweight Emco Compact 8 lathe with a solid tool post.This solved all of my previous parting off issues.
Mounting the parting tool upside down and running the lathe in reverse also helps in some cases. If you mount the tool in the regular way the cutting forces press the tool down and (on most lathes) towards the work. This increases the thickness of the chip which increases the forces... death spiral. In upside down mode the cutting edge is deflected away from the work.
Thanks John. I enjoy watching you piss about. I do a lot of that myself. Keep it up!!
Very useful guide, this is something I've struggled with in the past, thank you. I particularly enjoyed the subtitles :)
Pissin'' about not too bad . That's going in my little notebook of technical terms , just after piss wobbly slack.
Good sound advice, you do what it says on the tin.
Great video. I have been struggling with my parting tool. Now I know better Thank You John.
Very useful info John, many thanks.
Thanks for the instructions.
Man thanks for the tips.
Excellent information John, keep'um coming..
First time I've seen your Video , so l don't know what Brand of Lathe ! You have !
Harrison 140
Welcome to the channel
Thanks John
Thanks John fanbloodytastic 👍👨🏻🏭
Thanks
How can I thread in reverse (cutting away from the chuck)with a "screw on chuck and spindle " on my South Bend lathe?
Put the tool post behind the work. Watch Joe Pie. he will explain it better.
Awesome. Regarding speeds is there any official calculation to work it out for Parting off. You mentioned 300 rpm even for carbide so I think I've been running mine too fast.
If you consider how fast the carbide tools are cutting on a CNC machine it gives you some idea what they are really capable of. The secret ingredient to successful parting at high spindle speeds and feeds is lots of coolant to evacuate the chips and prevent overheating.
@@howardosborne8647 hi I've tried to google for speeds and feeds for Parting operations but had no success
I use the parting of tool upside down on the other side of the cross slide, This is how they were used on capstan lathes when I was an apprentice. The advantage is that it is on a single toolpost
which is more ridgid than the compound and tool holder. The weight of the chuck adds to the cutting force so both force the work peice down onto the bed. A bonus is that it free's a tool position
on my rotating tool holder.
fast speed slow feed 002"
I’d also suggest:- reduce chatter, lock ways on the main carriage & top slide.
- that the cutting tool is wider at the cutting edge narrow to the back to reduce side friction.
Check out “blondihacks”for lathe and milling basics instruction.