copy lathe

[gpigeon]

A friend has asked me about a wood turning copy lathe. I am more of a "metal worker" but I can see that there is heaps of timber expertise on this forum.
My mate is wanting to mount a 100mm angle grinder (fitted with wood cutting head) in the tool post and then turn odd (ellipitical) profiles in timber as it rotates in the chuck or between centres.
I understand that there are some "home-made" versions of machines out there that can do this! Have any of you guys built one of these? Any pointers to web sites or ideas????
Regards.
Bill.

[TTIT]

There's a thread running on that very topic here (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=52154) right now - but be warned! - some of them are getting a little upset about it! :shrug:

[reeves]

sounds like he may need more of a router lathe or milling machine setup.

Like the ones here

http://legacywoodworking.com/
(http://legacywoodworking.com/)
http://legacywoodworking.com/images/product/116.jpg

you can setup various ways of doing this on a standard lathe with attachments but its often a custom job as you mentioned, Vermec in Brisbane has some attachments that do this but form what yr explaining and copy lathe style attachment or router lathe might do it..just gotta be careful of the speed at which the lathe will turn compared to the speed of the grinder and the overal direction and accuracy of the cut..its probably just as 'easy' to to lock in the grinder and rotate the workpiece by hand into it as needed...;-)

this guy

http://www.johnmacnab.ca/

using custom aparatus and grinders to achieve his carvings from turned works..

http://www.johnmacnab.ca/images/moreimage.jpg

http://www.johnmacnab.ca/images/contactimage.jpg

and then you have the ornamental turning style of achieving those gaols...usinga cross slide vice and various specific attachments

http://www.teknatool.com/products/Specialised/ornamental.htm

http://www.teknatool.com/images/products/ornamental3.jpg

some other links here

http://www.the-sot.com/contacts.html

and the Assue OT group has various devices that have been custom made to do similar things...

http://www.pnc.com.au/~k_j/OTGA/Pages/GalleryEquip.htm

http://www.pnc.com.au/~k_j/OTGA/Pix/Equipment/DCP_0015.jpg

have fun...

[Hardenfast]

Great links, Reeves. Many thanks.

Holey Moley! That John MacNab guy produces some fascinating stuff. Mind you, I've seen a few posts like that, but I don't think they were meant to look that way. Many of those spiral pieces seem to be hollow - what do you think he's using as his material?

The Legacy site & equipment is also fascinating. Shame that all the best stuff always seems to be available in American specs only.

I noticed that there were quite a few demonstrating ornamental turning and techniques at the recent Sydney Wood Show. Many of them seemed to be using home made jigs with clamp-on grinders etc. It would appear I have quite a bit to learn before I could consider some of these things.

Good luck, Mr Pidgeon. Don't forget to post some comments or pics here if you have any success with your venture.

[reeves]

what do you think he's using as his material?



mostly lighter woods like elm, spruce, pine, beech and oak etc as a far as I can tell..he hollows them out somehow and gets them really light in weight

there was an article published in woodwork magazine a while back that explains how he does it in greater detail

http://www.johnmacnab.ca/woodwork.pdf


cheeeeers
john

[joe greiner]

Vern's (TTIT) link is for an entirely different application, i.e. hogging down an irregular shape to round.

Most of the lathe duplicators and copy lathes (Googled each of these) are used for axisymmetric turning, usually at full speed of the lathe following a stationary original. The Legacy-type machines are closer to what you're chasing, but you'd need a mechanism to rotate the original in sync with the workpiece. Often used for making smoking pipe bowls, rifle stocks, golf club heads and such. Depending on your follower apparatus, the original may need an exaggerated cross section. For example, with the router base pivoted at one end, and the follower twice the distance from the router bit, the original's cross section would have to be twice the desired diameter of the workpiece. (Hope that makes sense.) On those, the workpiece turns at slow speed or by hand.

Google with some added keywords might help.

There's a product called a "duplicarver" or something like that, which might be close to your idea, or provide food for thought.

Here 'tis: http://www.terrco.com/woodcarvers.php

Joe

[Skew ChiDAMN!!]

Bill, you mentioned elliptical turning... would this be for ovalled boxes or similar?

'Cos it's fairly simple to make a lathe to do this; it's only half of a Rose Engine. (See the Ornamental Turning forum for descriptions of Rose Engines or try here (http://home.vicnet.net.au/~pwguild/o-rosego.htm) for a full-blown RE. You only want the rocking system out of this, though...) Roughly explained, you mount the whole lathe on sprung hinges so it can rock back & forth, mount a cam on an outboard faceplate to do the rocking and mount the tool-rest to the bench the lathe is rocking on, instead of the ways themselves.

Changing the profile of the cam will change the profile of the box; ovalled, squared, pentagonal...

Best turned by hand or geared way, way down to very low RPM though. :wink: