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Extracting Broken Bridge Screws

rumblinbass

rumblinbass

Aug 22, 2003
1,118
196
Wimberley, TX
#1
picked up a used MIM 60's Jazz from CL. Looks like it was well taken care of. Neck is good. Frets are in good shape.
Last night I decided to install a BAII I had and found that 2 of the bridge screws are broken in the body.

Is it possible to get them out of the body or am I screwed?:(
 
#2
If the head broke of flush with the body you might be able to use a dremel tool to cut a slot to get a screwdriver in. If not you might be able to use an extractor but that can be tricky if the screw didn't shear off level. Easier if you have a drill press.
 
#5
Jazzdogg said:
I keep Grabit (and micro Grabit) screw extractors in my tool bag to help students who break off screws in their projects. They're affordable, and they work - if you're careful, you won't damage the surrounding wood. :)

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Click to expand...

looks Grabit works only if the head of the screw is stripped.
the screws in my bass are broken. the head and about 1/4" of the shaft (unthreaded) broke from the threaded part of the screw. will try to post pics later.
 
#6
rumblinbass said:
looks Grabit works only if the head of the screw is stripped.
the screws in my bass are broken. the head and about 1/4" of the shaft (unthreaded) broke from the threaded part of the screw. will try to post pics later.
Click to expand...

It works either way. You use one end to bore a small hole in the exposed bit of the broken screw, then you use the other end to dig into the the bored hole and extract the screw.
 
#9
I recently had a similar issue. I ended up using an end mill to clear out the screw, drilled the holes larger and plugged it with a dowel. I didn't try a screw extractor, but probably should have (and saved myself a lot of work).
 
#10
I have an idea...
The difficulty with an extraction method (AFAIK) is drilling into the screw. The problem is that the drill bit has a tendency to walk and you end up drilling into the wood. I think I might be able to use a dental pick (I work with electronics and having a dental picks around is quite handy) as a punch - assuming that the screw is a softer metal than the dental pick. The diameter of the the dental pick is small enough to get down into the hole to the screw. Once the screw is punched the drill bit will have a divit to drill into and hopefully prevent it from walking into the wood.
I'm going to make a trip down the hardware store at lunch to see what kind of drill and extraction bits they have on hand. I'm worried that I will not be able to find an extraction bit that is small enough in diameter.
We'll see.
 
#11
A Grabit is my first choice because they work so well, and because they're less destructive to the wood and require less work.

If I need to use one of these:

Screw Extractor - Rockler Woodworking Tools

I make a plug ( http://www.rockler.com/product.cfm?page=10614&site=ROCKLER) using a plug cutter in the drill press) to fill the hole instead of a dowel. Dowels aren't ideal because you end up driving the replacement screw into end-grain (instead of face grain); screws don't hold as well in end grain (aditionally, the hole in which a dowel is inserted will sometime "oval" and become loose because of contrary grain orientation and differential expansion and contraction) .
 
#12
Jazzdogg said:
A Grabit is my first choice because they work so well, and because they're less destructive to the wood and require less work.

If I need to use one of these:

Screw Extractor - Rockler Woodworking Tools

I make a plug ( Hex Shank Tapered Plug Cutters - Rockler Woodworking Tools) using a plug cutter in the drill press) to fill the hole instead of a dowel. Dowels aren't ideal because you end up driving the replacement screw into end-grain (instead of face grain); screws don't hold as well in end grain (aditionally, the hole in which a dowel is inserted will sometime "oval" and become loose because of contrary grain orientation and differential expansion and contraction) .
Click to expand...

noticed in your first post you mentioned micro grabit. that looks promising.
 
#13
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Forget the extractors - you'll mess things up a lot worse if you don't use a drill press - and then you'll prolly end up breaking the drill bit or the extractor off inside the broken screw and then you're seriously screwed.
 
#14
rumblinbass said:
noticed in your first post you mentioned micro grabit. that looks promising.
Click to expand...

Thankfully, they work really well. Their small size allows them to function even when a screw's head is missing completely. I use a spring-actuated center punch to create a detent that prevents the drilling end of the Grabit from skating.

If the screw head is intact, but mangled, I am sometimes able to withdraw screws using an impact driver instead of a drill/driver; a little valve grinding compound provides just enough grip for the driver bit to engage the screw head, and the tap-tap-tap motion of the impact driver (mine's a 15.6 volt Panasonic) works better than the relentless torque or a normal drill/driver.
 

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