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Bridge Clamping Question
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Author:  jhowell [ Mon Dec 11, 2006 1:39 pm ]
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The question I have dovetails with Hesh's post on cauls. I made this clamp from some maple scraps and a couple of tongue depressors because of how slow I was when trying to set up multiple clamps/cauls in a more tradional method of gluing and clamping the bridge. The hardware are brass #6 screws. This method seemed to work really well as I was able to put enough slack in the system to hold everything together, but still have room to brush LMI white glue on to the base of the bridge prior to cinching things up. Glue cleanup was a breeze. My goal is to be able to move to HHG for this operation and I'm thinking about doing this clamp in lexan. So...

Because I am pretty green at all of this, I'd like to solicit some honest opinions about the differing methods of gluing and clamping bridges. It will obviously be some period of time before I really know how successful this was!

Photo's:



The clamp in place.




The clamp system. The bottom is a pair of tongue depressor's glued up. It is fairly flexible .
Author:  JJ Donohue [ Mon Dec 11, 2006 2:15 pm ]
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Nice clamp and method, Jim! It's a HHG natural...where's the challenge?
Author:  Serge Poirier [ Mon Dec 11, 2006 4:13 pm ]
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yup, very nice clamp set up!
Author:  Michael Dale Payne [ Tue Dec 12, 2006 2:07 am ]
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The only critical comment I can come up with is the wings are forced down by the end two clamp screws. I know that there is bracing directly under them, however I see no means of caul support to clamp against. I may be missing something here But I would like to have clamping support all across the bridge girth to avoid possible over flexing of the braces in order to clamp the wings securely. Other than that it looks great.MichaelP39063.4221875
Author:  Louis Freilicher [ Tue Dec 12, 2006 2:46 am ]
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For tracing braces I have used small rare earth magnets. You can move
them around and follow the braces inside and use the edge of the outside
magnet to trace their positions on a piece of paper or tape etc.
I have used this trick for making clamping cauls, making sure I have enough
room for pickup installations and taking bracing patterns.

So far so good.

I agree with Michael about having some support under the bridge wings if
you are going to be pushing on them.

Louis
Louis405239063.4498611111
Author:  Michael Dale Payne [ Tue Dec 12, 2006 3:21 am ]
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[QUOTE=Hesh1956] Michael I have noticed that some folks just use a patch for a caul that covers the bridge plate and other will have it cut out for the X legs and continue under the entire bridge.

I don't know which one is better but the later is a lot harder to make when you forget to make it before closing up the box....... Don't ask me how I know this...... [/QUOTE]

That is why God made Friendly Plastic
Author:  Wade Sylvester [ Tue Dec 12, 2006 3:35 am ]
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Jim, thanks so much for posting your clamp system!
As Hesh mentioned, it is crucial to make this internal extended caul before closing up the box.

As others do, I add “wings” that fit on the other side of each brace leg with a bit of space where it intersects the new extension. That way, the wing surfaces will conform to whatever radi the top has settled into. I add epoxy in the spaces that will “float” and fill in setting the wings to conform to the top.
My quick and dirty picture shows the whole caul assembly upside down.
I hope this helps,

Wade

Wade S.39063.4854861111
Author:  Andy Zimmerman [ Tue Dec 12, 2006 3:40 am ]
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Your bridge clamp looks nice. It looks almost exactly like the one I got from
John Hall.
Author:  jhowell [ Tue Dec 12, 2006 10:34 am ]
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Thank you everyone for the comments. I did close the box prior to making this though I can assure you that larger blunders have occured on this instrument.

I will take the wings on the caul into consideration on the next iteration of this device. My idea is to use lexan or plexi to build a more permanent version.

Had no clue this was close to a design of John's. Appropriate though, as the guitar is from his kit. Can't say enough about his helpfullness or his willingness to come up with these kits that are a little off the beaten path.
Author:  Greg [ Tue Dec 12, 2006 3:39 pm ]
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Great demo. Makes good use of the string holes to fix/register the bridge on the top plate. I like it.
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