advice to novice on repairing a broken neck on 3/4 bass

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Mit Wanzer
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advice to novice on repairing a broken neck on 3/4 bass

Post by Mit Wanzer »

Hi, If you can give me ANY advice on this repair it is very welcome. I am new to this kind of repair; I have never worked with hide glue; I plan to use the instrument as a beginner.
The repair by previous owner has parted and the neck was held by the tension in two deck screws inserted alongside a small dowel. I removed one of the screws but had to cut the other off (it is still in the base part of the heel -for good, I would say!) The dowel has been drilled out of the fingerboard side of the heel. I have washed off the glue with hot water and haven't done much else, such as planning placement of dowels and/or hardware or planning how to clamp the pieces when gluing. My questions are:
1. Is hide glue the right way to go?
2. Should I use a combination of dowel and hardware? Or, should I use two dowels?
3. Shouldn't the dowel(s) be much larger in diameter? What configuration would be best for their size, depth, and position?
4. What should I do about the recessed sockets which received the head of the deck screws?
5. How many clamps are needed?
What other advice would you give?
Thanks,
-Mit
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Michael Lewis
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Michael Lewis »

Go to your local library and request the violin repair book by Hans Weisshaar and Margaret Shipman. This book is a veritable college graduate course in repair of violin family instruments.

Since this neck has already been boogered it will take some ingenuity to make it work again. Dowels are NOT the answer! You may need to make a new heel, and a well fitting glue joint is preferable to a mess with dowels. Splines are usually stronger than dowels.
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Peter Wilcox
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Peter Wilcox »

Did you remove the fingerboard (I don't see it)? Do the screw holes go through it?

Do you want to "restore" this, or just get it into playing condition as simply as possible, cosmetics be damned?
Maybe I can't fix it, but I can fix it so no one can fix it
Mit Wanzer
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Mit Wanzer »

Since this neck has already been boogered it will take some ingenuity to make it work again. Dowels are NOT the answer! You may need to make a new heel, and a well fitting glue joint is preferable to a mess with dowels. Splines are usually stronger than dowels.[/quote]
Thanks, Michael!
The fingerboard was removed by me, yes. The dowel hole and the countersunk screw holes are beneath the fingerboard. I will add another photo.
I would like to get this usable. Cosmetics be damned!
-Mit
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Bob Gramann
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Bob Gramann »

Chuck Traeger's book,"The Setup & Repair of he Double Bass for Optimum Sound", has a chapter on this type of repair. He recommends the use of metal in some cases. I haven't had to fix one like this yet, so I don't know if I could bring myself to use bolts. That said, the book is excellent even though expensive. Applying his tips and principles greatly improved the sound of my plywood bass.
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Peter Wilcox
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Peter Wilcox »

Hey Mit, I know I'll catch some crap for this, but here's what I'd do.

Try to get that end of the old screw out. Even if you have to dig it out, or use a plug cutter, you can put a hardwood dowel/plug in there, then re-drill a screw hole .

Drill a new screw hole and head recess in the neck and the heel where the current dowel is. (I guess you took the dowel out of the neck portion - I'd glue a hardwood dowel in there to accept a screw hole.)

Scrupulously clean both faces of the break to get old glue off and the best fit possible for gluing.

Then, after dry fitting first with screws to make sure the neck still aligns well, apply glue and screw in the 3 deck screws, which I think will mainly act as clamps rather than being the main structural support. The important part is getting a good fit for the glue, which is what will hold this together.

I'd make the length of the screws long enough to grab at least 1 1/2 inches of the heel wood. I'd use Teflon coated screws which are easier to drive.

I don't think dowels will help at all - I think the clamping pressure of the screws is more important.

As far as glue, others here will have more knowledgeable input. I think hide glue would be fine, though more difficult to apply properly. I myself would probably use yellow glue, giving a longer set time in case I have trouble getting everything assembled quickly, which I usually do.
Maybe I can't fix it, but I can fix it so no one can fix it
Jason Rodgers
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Jason Rodgers »

You might consider contacting James Condino. He does this sort of thing every other day and could probably give you some advice on the hard and easy ways to go about this repair. I have a feeling Peter's suggestion will be the answer for the easy way.
-Ruining perfectly good wood, one day at a time.
Mit Wanzer
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Mit Wanzer »

Update: Thanks to all who weighed in!
I went with:
1. a 5/16 lag screw with hex head (especially since extracting one of the screws was impossible!). That was 5 inches long with a neat fitting washer under the fingerboard.
2. glue: lots of gorilla brand wood glue around the break and in the upper part of the joint, up against the block in the body and up against a little saddle/escutcheon of plywood (10 square inches; decorative curlicues) that I glued to the top as a kind of u-shaped surround where the neck is recessed into the body.
3. 3/4" dowel, about 4 1/2 inches long: glue!
4. clamps, time, prayer???
It is strung, now, and appears to be holding fine. There are some cosmetic issues, since I am quite a beginner, here. But with some attention in other areas, the looks have actually improved a lot.
OK.
Thanks again,
-Mit
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Hans Bezemer
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Re: advice to novice on repairing a broken neck on 3/4 bass

Post by Hans Bezemer »

Great that it worked out fine.
Do you have some pictures of the final result?
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