Clamping Separated Rib Corners from the Outside

[Brad Dorsey]

Does anyone have a simple effective way to apply clamps when regluing open rib corners from the outside?

 

Right now I am working on a cello that has several open rib corners.  I spent a few hours today devising a body-spanning clamping fixture that turned out to not work very well.  Herdim makes rib corner clamps for violin/viola and for cello as seen here:

 

http://www.howardcore.com/cgi-bin/shopper.cgi?preadd=action&key=735615

 

Do these clamps work well? 

[LinkMan]

 

http://artisanviolin.com/repairs.html

[LinkMan]

 

#63 Peter K-G

 

Starting first violin - Soundpost help

Started by Kimmo89, Aug 14 2013 04:13 AM

[tartarane]

Hello Brad

 

I bought these corner clamps sometimes ago.

I hardly use them

they have a knack to fall off as soon as you stop looking at them

the presure has to be spot on , the screws are to short to use "padding" underneath to regulate the presure on the whole hight and not only on the poits u can screw.

 

bad buy fro me and for two of my violin makers mates

we were stupid enough to buy three sets :-))

regards

tartarane

[Addie]

I have used one of these for violin

 

And if that didn’t work, I cut half-sections of pvc pipe to fit the curves, and used the same clamp.  It is quick and easy, and you know on the trial clamping if it will work or not.

[Brad Dorsey]

I tried a clamp just like that and it wouldn't grip.  It just slid off.  Sometimes I have been able to use something like that on a violin.

 

Here are some pictures of the contraption that I devised:

 

 

 

 

LinkMan:  Your pictures do not help me, because I am repairing an existing instrument with the top and the back on.

 

Does anyone else have any ideas?

[Addie]

I tried a clamp just like that and it wouldn't grip.  It just slid off.  Sometimes I have been able to use something like that on a violin.

Oh well.  Like I said, at least it’s not a time waster.  They either grip, or they don’t.  I also remembered the PVC was for a top-off job.

I do wrap the jaws with blue painter’s tape, which makes them less slippery.  

[Aaron Johnson]

I've seen people put generic clamps on around the corner, like you would if you were gluing a top on. And then, using the shafts of the clamps as crossbars, insert wooden shims/wedges in between the corner and the clamps to force it closed.   You just have to make sure you are getting the corner completely closed with the shims and not causing any varnish damage in the process.

 

When I've seen this method it has been when only one of the ribs on a corner is loose. I'm not sure if it would work so well if both ribs on the corner are loose.