Adjustable caul for gluing back bottom

[Roger Häggström]

Did a "thing" in my shop today. When gluing back the bottom I use a jig. One thing I haven't done so far is to protect the top when using clamps for the bottom. Not a problem until the day one of the clamps is missing the protective plastic top and you don't see it (happened to me recently!). Here is the guitar body in the jig waiting for a lot of clamps.

I made 2, 3 and 4 sets of spruce pieces connected with lashing wire. The set can be bent to follow the shape of the two curves of the bottom as shown on another loose bottom.

The hardest part was the drilling of the 1,5 mm hole in the spruce for the lashing wire. The drill wanted to follow the runout in the flatsawn spruce... The lashing wire is put through the holes and a 90 degree bend in the end keeps everything together and give some room for curving the set.

Looking forward to the next bottom gluing!

[Joshua Levin-Epstein]

Roger,

What is the source of those clamps? Frank (Ford) has a fixture like this but bench made the clamps (which leaves me in the dust). But if I can buy the clamps...

That flexible caul is really cool.

[Roger Häggström]

I guess you talk about the jig for the bottom gluing and the side clamps. I bought really cheap clamps and cut away the "stop" in the end of the bar just keeping the movable part with the clamp screw. I made some hard wood pieces of wood and fastened the remains of the clamp with one screw through the opening made for the clamp bar. The opening in the molded metal is quite wide and the "clamp" can be adjusted a couple of cm's up or down. In the front of the wood there is a metal angle screwed into the side of the wood. I then use short sheet metal screws to secure each clamp in the spot needed for the guitar body. The plywood  sheet is in soft spruce to make it easy to mount the screws, I have a wood distance under the sheet not to screw into the bench.

The guitar body rests on some scrap wood to give it the right height for the side clamps. Inside the guitar I have a cross made of adjustable round rods to shape the guitar sides to the bottom. The rods are "foldable" in pieces and can be removed through the soundhole.

I have some more pictures and a text in Swedish here.

[Steve Bettesworth]

They are the threaded part of a F clamp. 

[Joshua Levin-Epstein]

I get it. The threaded section looked solid but actually has an oblong hole (where the bar used to be). This was well illustrated in the link Roger provided.

Roger, Your English is much better than Google Translate. Thanks for the posting.

[Steve Bettesworth]

Fantastic  jigs on your link  Roger. Love the internal one.

[Roger Häggström]

Glad you liked it! :-)