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Cutting curves with a metal lathe.

Posted: Sat Feb 23, 2013 8:28 am
by Gershom
HOW?

I've been using my bits as a rest for my wood lathe tools... Seems like there would be a better way...

Jon

Re: Cutting curves with a metal lathe.

Posted: Sat Feb 23, 2013 8:56 am
by DMI
I used to do this but it means the angle of the blade is pretty screwed up, I ended up using two old tools and welded one under the other to make a rest at the correct height.

I now have a proper tool rest from a wood lathe that clamps through the bed.

Take a look on ebay.

David.

Re: Cutting curves with a metal lathe.

Posted: Sat Feb 23, 2013 11:21 am
by caskwith
I do it etch a sketch style using the handwheels but this technique isn't for everyone. I do the same to cut tapers on shanks and stems, with practice you can cut semi circular shapes and small tapers without too much difficulty, yesterday for instance I cut a 1.5 in 100 taper on a stem.

Re: Cutting curves with a metal lathe.

Posted: Sat Feb 23, 2013 11:26 am
by smokindawg
I made one. I used two pieces of angle iron and then made two shafts drilling a hole in one so that the other slides inside it. I drilled and installed a set screw so height could be set. I the. Welded one piece of angle iron flat on one end drilled to bolt to the cross slide on my jet. On the other end I welded a piece of angle iron set like a roof and this is my rest.

It sounds more complicated than it is.

Now I just remove the tool holder/small cross slide and bolt the rest on. Makes it nice being able too adjust the tool rest using the bed and cross slide.

Re: Cutting curves with a metal lathe.

Posted: Mon Feb 25, 2013 5:41 pm
by wdteipen
This is the one advantage a wood lathe has over a metal lathe. Many pipemakers use a wood lathe style tool rest adapted to their metal lathe and use wood turning tools to cut the curves. You can cut certain curves like the radius of stem beads on a metal lathe using custom ground cutting tools using blanks.

Re: Cutting curves with a metal lathe.

Posted: Tue Feb 26, 2013 8:38 am
by ToddJohnson
wdteipen wrote:This is the one advantage a wood lathe has over a metal lathe. Many pipemakers use a wood lathe style tool rest adapted to their metal lathe and use wood turning tools to cut the curves. You can cut certain curves like the radius of stem beads on a metal lathe using custom ground cutting tools using blanks.
I'm not sure it's an "advantage," necessarily, but it's certainly more of an "on label" use of the tool. My advice would be to learn how to cut curves using both wheels at the same time. Using specifically profiled tools to make plunge cuts is just going to burn the material and leave you with a lot of sanding. You do, of course, need specifically profiled tools for different purposes, you just can't use them solely on one axis. If you get a QCTP, which I would recommend, you can easily find a (wood) tool rest to fit it. You can use the boring bar as well. Good luck.

TJ

Re: Cutting curves with a metal lathe.

Posted: Tue Feb 26, 2013 9:05 am
by Massis
ToddJohnson wrote:
I'm not sure it's an "advantage," necessarily, but it's certainly more of an "on label" use of the tool. My advice would be to learn how to cut curves using both wheels at the same time. Using specifically profiled tools to make plunge cuts is just going to burn the material and leave you with a lot of sanding. You do, of course, need specifically profiled tools for different purposes, you just can't use them solely on one axis. If you get a QCTP, which I would recommend, you can easily find a (wood) tool rest to fit it. You can use the boring bar as well. Good luck.

TJ
any hints on where to find such a tool rest for a QTCP?
I have a myford super 7 with QTCP (best piece of tool it has! by far.), but I'm still looking for a decent tool post solution for wood turning.

I know a full size wood tool rest exist that clamps to the bed, but I'm quite sure it would get in my way too much...

Re: Cutting curves with a metal lathe.

Posted: Tue Feb 26, 2013 3:21 pm
by caskwith
Just get a nice long bit of 1/2 steel and put it in a spare tool holder.

Re: Cutting curves with a metal lathe.

Posted: Tue Feb 26, 2013 5:32 pm
by Growley
caskwith wrote:Just get a nice long bit of 1/2 steel and put it in a spare tool holder.
Same here. I think it's called key stock maybe??? You a find it at ACE or Lowes / Home depot near the threaded rods. Works well for me. It's under $10 too!