Segmented Turning Glue-up Jig

Too much work for me. I use band clamps - those metal clamps sold at auto parts shops that look sorta like a ladder and you just turn a screw to tighten/loosen them. Huge range of sizes, cheap, and they apply pressure uniformly around the segments...

...Kevin

Check this page out, he uses rubber bands:

AHA! Another gadgeteer trying to re-invent the wheel, eh? ;-)

I can't see much wrong with the idea, although I think it would be kind of cumbersome. You'd probably want it on a turntable (lazy susan bearing thingy) since you'll have to tighten each rod a little at a time, evenly all around. The ends of the rods may want to put a twisting force on the segments as the pressure is increased, but a clamp disk on top will help deal with that. Instead of flat ends on the rods, I'd grind them with a rounded point or maybe just slightly convex would be good enough. You'll need to somehow keep that clamp disk from being glued to the segment ring--wax it, or? Shouldn't take more than a couple hours to slap together, I say go ahead and try it. But there are other ways, less cumbersome--many segmented turners use band clamps, large hose clamps, or rope tournequets. If your segment angles are right on, that kind of circumferential pressure will do just fine. You may still need a clamp plate, but will only have one screw or twister-stick to tighten instead of 12.

Ken Grunke

I've thought of that, but IMHO the pressure points need to be at the seams, not the faces, with V-shaped blocks, so that the pressure keeps the faces lines up.

OTOH, I was thinking about servo-actuated clamps, so that the computer can keep them in sync. I suppose a simple ring gear system, like the supernove chuck uses, would work too. Sixteen jaw chuck anyone? Maybe a longworth chuck? You'd need a top plate to keep the pins aligned though.

"Greg G." wrote: (clip) Aside from the 6 feet of all-thread and construction time, I wonder if this would work well enough to bother building...? ^^^^^^^^^^^^^ First, Greg, I want to compliment you on a really nice job of graphics. Now to the nutz and boltz. Two lengths of All-thread are very cheap. But, you will also have to have a matching threaded insert for each piece of All-thread to go into. And, what about some means of turning the threads? Surely you are not going to make a beautiful jig like this, and then use pliers.

My reaction is that it is too much work, to solve a problem that has already been solved with a simple band clamp.

How about arranging the rods so they slide instead of screw and form them in a U that connects to a scroll chuck underneath and tightens them all at one time and makes them all self centering.

Brian

Thanks, everyone, for the suggestions. I use strap/band clamps now, but had a moment of idle time to ponder other possibilities. I'm with Kurt Vonnegut on this one - consider your options.

It only took a few minutes to create the CAD drawing. Yes, knobs would have been included - I just didn't feel he need to draw them, (Dawr them - for you Bostonians.)

Tightening all those screws is a bit much - but servo mechs, although interesting from an engineering standpoint, are not practical. Pneumatic clamps, however... Hmm...

Gadgeteer? Absolutely. It's my reason for living... Just Another Gadgeteer? Never! Reinventing the wheel? Nah, just searching for another way to do something more efficiently.

I think this particular project is not practical, but after gluing up a few more rings last night, I think I've got another bonehead idea...

FWIW,

Greg G.