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useful clamp
http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=6831		 Page 1 of 1
Author:  charliewood [ Wed May 24, 2006 5:20 am ]
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I have been building alot of clamps lately, trying to make whatever I can - mainly spool and gearing up to make some klemsia type cams.
I was perusing an issue of ShopNotes {I havent forgotten Serge }
And I came across this shopbuilt clamp.

I was thinking this could be useful in guitar building, seeing as they are deep reach {or could be made so}.
Im sure there isnt as much pressure as a cam, but still these are good for something, mabye even I could add a cam to the end of these for extra clamping pressure?
opinion?
Cheers
Charliewoodcharliewood38861.6071064815
Author:  CarltonM [ Wed May 24, 2006 5:29 am ]
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Thanks, Charlie. Could prove useful.
Author:  Serge Poirier [ Wed May 24, 2006 7:40 am ]
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Thanks Charlie, these are really neat and easy to make, file saved bud!

Serge
Author:  Philip Perdue [ Wed May 24, 2006 8:00 am ]
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Does anyone think that this could be used to clamp bridges?

Philip
Author:  Serge Poirier [ Wed May 24, 2006 8:03 am ]
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Philip, i sure think so, you would just have to make sure of the distance needed for the throat IMHO.
Author:  charliewood [ Wed May 24, 2006 8:08 am ]
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What I wondered about was clamping pressure - I wish one of our technical bretheren would chime in here because Im sure someone here {prolly alot of folks} know quite a bit about clamping pressure.
This is why I was considering a Klemsia hybrid with this design. Mabye its not needed though - Anybody?
Cheers
Charliewood
Author:  Serge Poirier [ Wed May 24, 2006 8:12 am ]
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Charlie, though i'm not an expert on clamping pressure, i sure would trust the arches and the threaded rod plus the wing nut, the clamping point has no choice but to apply real strength in my VHO! looks promising!
Author:  tl507362 [ Wed May 24, 2006 9:15 am ]
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It doesn't look like it would produce enough clamping pressure for guitar building because the clamping pressure is happening at the back end of the clamp, and not over the piece that holds the piece in place. Notice that on a cam clamp, the clamping pressure is at the tip of the clamp, and this is at the back of the clamp. I'm sure it would be good for some projects that do not require tight clamping pressure. You should just make one and test it. It may be good. Good luck!
Tracy
Author:  KiwiCraig [ Wed May 24, 2006 10:31 am ]
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I'm with Tracy on this one . A poor substitute for a cam clamp. Can't see much strength about it because of the bolt being so far back from the jaws.
It would also be limited to jaw opening .The jaws would not be parallel as cam clamps are.
My advice Charlie ..... Forget it ! and go for the cam clamps

Regards KiwiCraig
Author:  A Peebels [ Wed May 24, 2006 1:25 pm ]
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Kiwi I have to politely disagree. It looks like a good design to me. I'll make one up and measure the clamping pressure. I know that the leverage is wrong for efficiency, but the screw should still produce plenty of pressure. I'll send out a report when it's done. In the mean time, will someone measure the pressure produced by a cam clamp.
Thanks

Al
Author:  charliewood [ Wed May 24, 2006 3:02 pm ]
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[QUOTE=KiwiCraig]
I'm with Tracy on this one . A poor substitute for a cam clamp. Can't see much strength about it because of the bolt being so far back from the jaws.
It would also be limited to jaw opening .The jaws would not be parallel as cam clamps are.
My advice Charlie ..... Forget it ! and go for the cam clamps

Regards KiwiCraig[/QUOTE]

I wasnt actually considering substituting these for cam clamps, but rather incorporating the elements of a cam clamp mechanism onto the end of this design in order to increase the clamping pressure of the design.
Basically this design with a cam lever on the end - theoretically, being able to sinch it down with the butterfly nut first, and then adding the cam pressure, would amount to a heck of alot of clamping pressure,.
Also I would be deepening the reach of this design as well to make it suitable for guitar work.
Ill have to whip a couple up and see how they work.
Cheers
Charliewood
Hey A Peebles, thanks for doing a little research on the clamping pressure. charliewood38862.0018518519
Author:  Serge Poirier [ Wed May 24, 2006 3:07 pm ]
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I'm with Charlie, Thanks Al!

Serge
Author:  PaulB [ Wed May 24, 2006 3:47 pm ]
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We use clamps that work the same way as this for holding glassware on a retort stand in the laboratory. We use them for precisly the reason kiwi says - you can't crank em down all that hard.





*Edit* You do have great control over how much force you're applying though.PaulB38862.0447916667
Author:  Serge Poirier [ Wed May 24, 2006 4:11 pm ]
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I'm gonna wait untill Al Peebels comes back with his results, just a gut feeling i have that these might be good, especially if the head of the carriage bolt can be locked in the square hole at the bottom of the clamp.Serge Poirier38862.0500115741
Author:  Philip Perdue [ Wed May 24, 2006 5:11 pm ]
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I think that their would be an increase in clamping pressure if the hinge was longer. The change in fulcrum points could increase the clamping power based on the position of the bolt and the angle on the arms.

Philip
Author:  Serge Poirier [ Wed May 24, 2006 9:55 pm ]
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Sounds good also Philip !
Author:  Michael Dale Payne [ Thu May 25, 2006 1:31 am ]
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I like tht idea but I think I would add this type of clamping at the end
Author:  CarltonM [ Thu May 25, 2006 2:25 am ]
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Michael,

How do you keep the threaded rod from chewing into the jaw when pressure is applied?
Author:  Philip Perdue [ Thu May 25, 2006 3:08 am ]
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Carlton, I think I’ll jump in on your question. Looks like a perfect place for T-nuts. Use the appropriate size t-nut for the bolt and use a too small t-nut on the surface that the bolt will tighten on to protect the wood.

Philip
Author:  Michael Dale Payne [ Thu May 25, 2006 3:14 am ]
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There is a backing plate between the wood and the threaded rod on some and a plastic pad on the rod on others. My grandfather built som really big clamps that he used in his cabinet shop and he use wooden screws in them. Wished I still had them
Author:  CarltonM [ Thu May 25, 2006 7:15 am ]
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Michael...Thanks. I thought it must be something like that, but I wanted to make sure.

Philip...That seems like a really good solution, but I think that there's just not enough wood there to attach a T-nut, even if you clip the prongs. Hmm...maybe a too-small washer would epoxy in there...
Author:  Dread1916 [ Thu May 25, 2006 1:42 pm ]
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I like the simplistic design, but, I'd recommend the T-nut as some one had already suggested for the bottom jaw. But I would also opt out of the wing nut...I'd go with a heavy coarse thread and use a hex nut and then tighten this baby up with a wrench (Socket preferrably)

Additionally, I also think that a secondary means of applying pressure at the end of the jaw would be great (MichaelP---good idea)

With a bit more design work...this could be a great bridge tool...IMHO...

JP
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