Has anyone "made" their own twin screw vise?

[Zach England]

I don't mean with wooden screws. I mean has anyone used two tail-vise screws and successfully rigged them up with a chain drive so you only have to turn one? It seems like it would not be difficult IF one could find the proper gears (cogs?).

[Jay Maiers]

I don't mean with wooden screws. I mean has anyone used two tail-vise screws and successfully rigged them up with a chain drive so you only have to turn one? It seems like it would not be difficult IF one could find the proper gears (cogs?).

The chain drive itself is an easy task: two screws, two drive sprockets, and an idler sprocket or some sort of tension pin(s). Accounting for slop in the mechanism, adjusting the vise, or getting it to skew could be a bit of a problem.

Check out http://www.surpluscenter.com/powerTrans.asp
I've picked up a number of smaller sprocket and chain components from those folks.

[Zach England]

The chain drive itself is an easy task: two screws, two drive sprockets, and an idler sprocket or some sort of tension pin(s). Accounting for slop in the mechanism, adjusting the vise, or getting it to skew could be a bit of a problem.

Check out http://www.surpluscenter.com/powerTrans.asp
I've picked up a number of smaller sprocket and chain components from those folks.

Why would I want it to skew? Isn't that what I am trying to avoid by using the chain drive?

How would I mount the sprockets on the existing tail vise assemblies?

[Matt Meiser]

I made my own from 2 Lee Valley screws but didn't put a chain between them. It might be slightly easier to use but its not bad at all now. I always figured I'd bum some sprockets and chain from one of my bike-crazed brothers to connect them if I wanted.

[Jay Maiers]

Why would I want it to skew? Isn't that what I am trying to avoid by using the chain drive?

How would I mount the sprockets on the existing tail vise assemblies?

Fair warning: I've played with a chain drive vise exactly once, and I've never used one in a work environment. Everything that follows is based on my understanding of the vise and not on practical experience.

Most of the time I'd say you don't want it to skew, but maybe there are times when you have an odd-ball panel, something tapered? I really don't know. It's just a point to consider.

Looking at their tail-vise screws, I think you'd have to remove the handle and have the threaded portion of the shaft machined to provide another inch or so of bearing surface (creating a space between the bearing flange and the handle), and then buy the appropriate diameter sprocket.

IMO, If I had enough vertical space for the hardware, I'd start from scratch and buy a couple of lengths of 1" x 4 or 5 TPI acme threaded rod, 1" bore bearings, sprockets, and handle fittings to eliminate machining, and some matching nuts. Have a metal fabricator cut some sort of mounting flanges and weld them to the nuts. That would probably be a cheaper option than machining the screws, but it would be bulkier and not nearly as pretty.

All of that said, I would probably skip this operation unless I really enjoyed messing with things of a mechanical nature. The LV version would be a great investment with nearly guaranteed satisfaction and excellent customer service. The DIY version will be a PITA and there's always the possibility of failure or a sub-par piece of equipment.

As for myself, I like these kinds of challenges and would likely try it :)