Lathe Components ?

[chamcook]

Hi.,
Does anyone out there know of suppliers for lathe components which I could incorporate into my ShopBot? I need a gear motor, tailstock, live center etc. The idea is to operate the lathe using the accessory channel. This way the machine could perform a milling operation on one surface of a piece of stock (with the lathe holding the piece steady) and then the lathe could flip the piece over allowing the machine to mill another face.The lathe could also be set to spin continuously for normal turning.
I have planned a steel table with a recessed area for the lathe. My machine is oversize ( 5 x 12'). The last foot of cutting area at the back of the machine will be dropped down so that the center of the lathe is at the same height as the surface of the table. The lathe will have a swing of about 6 inches over its bed and a length of about 12'.
I have been trying to get a line on the lathe parts for a few months now without any luck. If anyone knows where I should look I would be very gratefull. If anyone has built a stepped (indexed?) lathe into their machine I would really love to hear from you.
Thanks in advance, David Needler

[bruce_clark]

David,

I have built a 4th axis, but it was not for a
ShopBot. It was for a mill/drill. It consisted
of a Vertex 6" rotary table, a 6.25" Bison 4 jaw
chuck and some modified 1:1 timing pulleys/belts.
All driven by a 450oz/in stepper motor. It can
do about 60rpm (probably too slow for turning but
GREAT for cutting steel, brass, aluminum and
Delrin).

Bracket was made on mill/drill and timing pulleys
were modified on lathe. If you are interested in
pictures of unit, will be more than happy to email
them (~700K).

No reason why this could not be used on a ShopBot,
but again, the RPM would be too slow to "turn"
wood, but you could mill/route spirals, do multi
surface work (one the same setup).

BTW, I believe someone else (can't remember his
name) added a 4th axis to their ShopBot, for
doing scroll work/spindles. They were doing
old style furniture restoration/reproduction work.

Bruce Clark
bwclark@centurytel.net (mailto:bwclark@centurytel.net)

[jimt]

David,

I'm just finishing up building a large lathe (24" dia. x 15' capacity), using 2 pillow blocks for both the headstock and tailstock. They slide back and forth on the side rails. It's not perfect, but it will be OK for limited production work. Anyway, the tool bit will be a router driven both lenghtwise and crosswise using Shopbot-style mechanics and steppers. When turning large items I plan to rotate them slowly to get a 1-2 ipm cutting feed rate. This will eliminate a lot of problems with large turnings, the worst one being trying to balance the piece. I've tried turning by hand before on large things and it's scary at best. So, a small gear motor is all that's required for turnings. Speed is dependent on the circumference of the piece, but 10 RPM should be plenty and then I have a speed control to slow it down from there. Also, I am planning on having a stepper motor attachable to the headstock for doing rotational indexing using a gearbelt drive. The faceplate I'm using is an old gearbelt pulley with some holes tapped in the side to mount things to, so I can attach the stepper there. Hope this helps.

Jim

[chamcook]

Bruce and Jim,
Thank you both for your responses.Things are becoming a little clearer. I would appreciate the photos you mention, Bruce. My e-mail address is chamcook@nbnet.nb.ca (mailto:chamcook@nbnet.nb.ca). Do you have sources for the Vertex and Bison components you mention?
Another response via e-mail pointed me to MicroKinetics Corporation who deal in this type of equipment. The parts listed on their site are a little small for my intended setup but there may be more in their catalogue.
I hadn't considered building the whole thing from scratch as Jim has. With no experience or tools to fabricate the variuos parts I would probably be getting in over my head.
It might be practical, however, to start with a fairly basic wood lathe , stretch the base, and mount it to the machine. When doing actual turning the motor that comes on the lathe could be used. When doing milling operations where the stock is held still or rotated slowly the lathe could be driven by a stepper motor which is added on much as Jim is talking about. Any thoughts?
One other thing. ShopBot talks about a "rotary indexer". The MicroKinetics people also sell an indexing attachment for their lathe. If you are driving your lathe with a stepper motor do you also need a rotary indexer or is this for lathes that are powered by other means?
Thanks again, David Needler

[Ron B]

David,

ENCO, J&L and other 'machinery suppliers' all have rotary tables and the associated chucks. You might check out the pictures on MAXNC's web site and Shurline. Both have stepper driven rotary tables.

Threading operations on non-stepper driven lathes require some rather sophisticated encoders to keep track of the spindle. I suspect the 'rotary indexer' SB speaks of is simply a horozional or vertical axis rotary table style device.

One could also build a very accurate indexer with speed reduction device salvaged from one of many sources.

HTH,
Ron