In case anyone is looking for one, Enco sells 2-jaw scroll chucks. I just bought a 6-inch for my new (to me) lathe, and it seems quite good for the price, and the 2-piece jaws mean it will be fairly easy to attach whatever custom jaws I can whack together. I haven't gotten the backing plate fitted yet, so I haven't actually used it, but can't see why it wouldn't work.
http://www.use-enco.com/CGI/INLMK3?PMK0NO=316059
2-jaw chuck
The chucks come with a plain back with about a 1/2" shoulder, creating a recess about 1/8" deep in the center. You have to buy a backing plate that fits your lathe, or make one. Chucking a chuck in your chuck is ok so long as you don't have to remove it between operations, but it's a little roundabout, adding length to your setup, and length always means flex. And, since most chucks introduce a few thousandths centering error, it might not put the center in the center, which may not matter so long as you're careful with your block placement. Still, better to get the backing plate that mounts on your spindle, which you then fit to the chuck by mounting the backing plate on your spindle and turning down the edge of the plate so the chuck fits very snugly and is centered to your lathe. Then you drill holes for the mounting bolts through the plate and you're in business. Even if you wanted to thread the end of a 1" rod and buy a backing plate that mounts to a 1"-8 tpi spindle, you'd still need to machine the backing plate, so you might as well do it right to start with. If you really want the rod mount, a woodworking 4-jaw scroll chuck is a better option.
Converting the Bison into a swivel-vise would take a mother of a ball joint -- these chucks are NOT light, and intentionally putting one off-center would also take a mother of a lathe not to shake the house down. Better to use something light like a woodworking 4-jaw chuck.
Converting the Bison into a swivel-vise would take a mother of a ball joint -- these chucks are NOT light, and intentionally putting one off-center would also take a mother of a lathe not to shake the house down. Better to use something light like a woodworking 4-jaw chuck.
Hi Jack,
When making a backing plate, how do you determine where to drill the bolt holes?
I recently got a 4 jaw self centering chuck for my Enco lathe and was lucky enought that the backing plate for the original 3 jaw chuck had hole placements where I needed them. I only had to turn down that center part to give a really tight fit, and the chuck works great.
I can order the undrilled and pre threaded (for the spindle) backing plate from Littlemachineshop.com for this same chuck. It has instructions on the site about how to drill the bolt holes, but I have not been able to visualize how to do it.
My question is: When the plate has no holes, and the chuck does, how in the world do you determine exactly where to drill the hole so that they line up with the threaded ones that come on the chuck? When you place the backing plate over the back of the chuck, you're blind as to where the holes should go.
Do you know how to do this?
Rad
BTW, I agree with you about chucking up *another* chuck in your lathe chuck. The further out you go, the more room for wobble and error.
When making a backing plate, how do you determine where to drill the bolt holes?
I recently got a 4 jaw self centering chuck for my Enco lathe and was lucky enought that the backing plate for the original 3 jaw chuck had hole placements where I needed them. I only had to turn down that center part to give a really tight fit, and the chuck works great.
I can order the undrilled and pre threaded (for the spindle) backing plate from Littlemachineshop.com for this same chuck. It has instructions on the site about how to drill the bolt holes, but I have not been able to visualize how to do it.
My question is: When the plate has no holes, and the chuck does, how in the world do you determine exactly where to drill the hole so that they line up with the threaded ones that come on the chuck? When you place the backing plate over the back of the chuck, you're blind as to where the holes should go.
Do you know how to do this?
Rad
BTW, I agree with you about chucking up *another* chuck in your lathe chuck. The further out you go, the more room for wobble and error.
Taking it as read that there's probably a difference between how *I* do something and how it should be done . . . when I did this once before, I turned short pointed steel dowels that just fit inside the holes and protruded just a smidge, and used them to tranfer the positions to the plate. And, I drilled the holes a little oversize, reasoning that the centering would be done by the turned shoulder and the bolts just snug it up. This one, I plan to take to a machinist friend and use his indexing table, but if that doesn't work I'll probably make some more pointed dowels. I'll do lots of things myself, but if it seems likely that I'll screw up a couple hundred bucks worth of steel, I'm not too proud to seek professional help.