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Cutting an offset cam
- Thread starter kelroy
- Start date
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British Steel
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Hi Kelroy,
Not a clue what a clock tailstock is, but assuming it's a cylindrical cam rather than lobed...
If you have a 4-jaw, centre the part on the *finished* "main bearing" axis and clock it to your standard of accuracy, then with the jaws at 3-6-9-12 o'clock, bring a dial gauge up to the work and adjust opposite jaws to the required offset.
If you only have a 3-jaw, make a shim to put between one of the jaws and the part for the offset - this requires a bit of calculation (moderate trig'), or some cut and try, measuring the offset with a dial indicator... I'd use cut and try!
If it's lobed, that's a fish of a different colour...
Just my ha'pennorth,
Dave H.
Not a clue what a clock tailstock is, but assuming it's a cylindrical cam rather than lobed...
If you have a 4-jaw, centre the part on the *finished* "main bearing" axis and clock it to your standard of accuracy, then with the jaws at 3-6-9-12 o'clock, bring a dial gauge up to the work and adjust opposite jaws to the required offset.
If you only have a 3-jaw, make a shim to put between one of the jaws and the part for the offset - this requires a bit of calculation (moderate trig'), or some cut and try, measuring the offset with a dial indicator... I'd use cut and try!
If it's lobed, that's a fish of a different colour...
Just my ha'pennorth,
Dave H.
- Joined
- Nov 21, 2010
- Messages
- 1,600
Be a piece of cake if you have the one to copy, all Im seeing is an eccentric, lets say that jams the quill. If thats what
you are looking at, the center (drilled hole) should be slightly off center. The more the offset will be less aggressive.
You want a gradual climb. These ware at the top of the climb gradually losing little by little until it zeros like being
round again. As Hopeful said, best done on a 4 jaw. Hope it helps, my biggest problem is connecting my hands to
brain to put in words. People creature of habits > what I do old school= locking tailstock quill i run it up and just
bump it with my palm thats enough unlike these kids in school half to slam it, not good. Hopeful this helps a little.
My brains are in my hands, not head samuel
you are looking at, the center (drilled hole) should be slightly off center. The more the offset will be less aggressive.
You want a gradual climb. These ware at the top of the climb gradually losing little by little until it zeros like being
round again. As Hopeful said, best done on a 4 jaw. Hope it helps, my biggest problem is connecting my hands to
brain to put in words. People creature of habits > what I do old school= locking tailstock quill i run it up and just
bump it with my palm thats enough unlike these kids in school half to slam it, not good. Hopeful this helps a little.
My brains are in my hands, not head samuel
- Joined
- Jun 17, 2011
- Messages
- 2,070
There are plenty of articles on making that modification on mini-lathes. If yours is bigger, just scale it up. This link is very close to the one I made for mine.
http://www.mini-lathe.com/Mini_lathe/Modifications/Camlock_tailstock/Camlock.htm Very well presented and in keeping with what dalee said.
Just Google "mini-lathe cam lock" to find more.
http://www.mini-lathe.com/Mini_lathe/Modifications/Camlock_tailstock/Camlock.htm Very well presented and in keeping with what dalee said.
Just Google "mini-lathe cam lock" to find more.
- Joined
- Jun 17, 2011
- Messages
- 2,070
Seems to me I turned the relief on the bolt by offsetting it in the lathe chuck. Your radius will be a touch bigger than that of the bolt. For that matter, since the relief doesn't do anything but allow the tightening mechanism to drop down a touch, you could do that part with a file.
Other parts should be possible with a hacksaw and file, as well as any drilling and turning jobs. If you have a four-way toolpost, you might be able to do a bit of milling on your lathe. Good time to put a milling attachment on your project list.
Other parts should be possible with a hacksaw and file, as well as any drilling and turning jobs. If you have a four-way toolpost, you might be able to do a bit of milling on your lathe. Good time to put a milling attachment on your project list.