Reduce clamp shaft?

[10shoe]

I recently purchased a really nice swivel clamp (Head TE-3600) but the shaft diameter is 12.38mm and I need it to be 11.97mm. Before I go hunting for a machine shop I thought I would ask whether anyone here has ever successfully had a clamp shaft reduced. If the shaft were removable from the clamp then I can see putting it on a lathe. But if the clamp head and shaft are all one piece (I think that's the case, not sure) then I'm wondering if it's even possible. Anybody ever had this done? Thanks!

 

[Wes]

@10shoe,

I, personally, haven't done this, but I know someone who did.
However, I don't know just what was involved. I can ask him more about it.

Suffice it to say, even the owner of the clamps may not know quite what was done.
It seems unlikely that the machinist would feel the need to explain the particulars to the owner.

 

[kkm]

I know someone who had it done on clamps with the head and shaft in one piece.

 

[10shoe]

Thanks guys! I guess it can be done then. I used to have a machinist in my neighborhood who liked to get non-automotive work once in a while. But he's long gone. So, I have some hunting to do.

I really like the design of this clamp. Won't know about it's performance though until I can get it on my machine.

 

[CVT]

If you don't need perfect aesthetics, I would bet that a diamond or aluminum oxide sanding bit on a Dremel would get the job done. That might not need a machine shop. Be warned that I have never done that myself. You might also be able to do it by hand, rotating the shaft in a piece of sandpaper.

 

[fritzhimself]

If you don't need perfect aesthetics, I would bet that a diamond or aluminum oxide sanding bit on a Dremel would get the job done. That might not need a machine shop. Be warned that I have never done that myself. You might also be able to do it by hand, rotating the shaft in a piece of sandpaper.

Holy crap - this is going to go wrong fast.

 

[diredesire]

I can't imagine that the head and shaft are one piece... that'd be very expensive to manufacture. Assuming they're separable, you can probably adapt the thing to a drill chuck and use wet sandpaper to reduce the diameter. It won't be incredibly precise, but should get the job done.

 

[kkm]

It would be better to take it to a machine shop. They might charge 70 bucks a clamp, but it would be worth it. Even if one of the shafts has a bit of chatter, the result will be much better than an amateur attempt that IMHO would probably compromise a clamp that’s not inexpensive.

 

[mill]

If we're thinking about the same clamp, these are one piece investment cast parts to the best of my knowledge. You can see from the relief at the base of the clamp shaft and the circular tool path on the bottom of the clamp jaw, also there's a hole with a chamfer at the bottom of the shaft for the tailstock. I'm pretty sure these were turned with a custom jaw and a tail stock. It would be difficult and expensive to find a machine shop willing to do this, it would be alot of work to setup a two jaw chuck and adjust it while indicating the shaft.
Remaking the tube the shaft sits in on your existing clamp base would be easier, remove the tube and measure the thread profile. This would be a simple part with most machine shops with a lathe, turn a profile and thread and drill and bore to the diameter that you want.

 

[kkm]

IMHO remaking the tube might be easier, but reducing the clamp shafts would make the clamps fit in the narrower tubes or the wider tubes.

 

[jim e]

Anyway you look at it, your going down the tubes, or your going to get the shaft

 

[10shoe]

@mill

Thanks for the INFORMED response. Glad to hear from someone who knows metal working. Personally, I've used a lathe maybe 2 times in my life. I couldn't picture how this shaft reduction could be done on a lathe but that's the tool I'd imagine you'd use.

So, I'm wondering a couple things:

If the shaft was made longer by tapping the end of the shaft and then screwing an extension to it, there'd be something for the turret to grab but no support at the tail stock end. Would that be dangerous for the machinist? Would it work to get the job done?

Alternatively, instead of spinning the string clamp at high speed, could the job be done with a surface grinder? So, rotating the clamp shaft once in front of a spinning abrasive stone?

Edit: BTW, my objection to modifying the tubes is that I use two sets of clamps when I do hybrids. I use diamond dusted clamps for the softer strings (like gut) and I use 3 tooth Toyo Zouki clamps for the monofilaments. I also have a couple thin profile clamps for tight spaces. In any case, everything else is 11.97mm.

 

[struggle]

Any decent machine shop WILL be able to accomplish this, Just gotta find the right one....

 

[jim e]

@Steve Huff on these forums had a couple clamps machined down to fit his machine a number of years ago. I recall he just brought them to a machine shop. It can be done.