Strap lock screw broke off in the neck of my Dot. What now?

[thendrix]

I have a strap lock screw broken off flush with the back of my guitar. I have tried drilling the screw out but I am afraid to go any farther as it keeps slipping off the top of the screw and making the hole a little bigger. I work in a machine shop and brought it to the shop and gave it my best effort with all available resources but with no luck. Can I fill the area with some kind of wood putty and move back toward the body a 1\4" or so and put a new screw in? What else would you suggest? BTW, it's an Epiphone Dot and it being a semi hollow, drilling additional holes kinda scares me, but if it can be done I'll try it.

[Tommorichards]

How far in is it? Cos if its near the surface, cut a horizontal slot in the top with a dremel or similar, and use a flat plade screwdriver to remove it. I have done it successfully on several screws over the years.

[Jazz P Bass]

Might want to try this extractor.
Link: Amazon.com: Alden 8430P Pro Grabit Broken Bolt and Damaged Screw Extractor 3 Piece Kit: Home Improvement

[jrfrond]

Here's a trick I've used on several occasions, learned from Dan Erlewine: you need to get yourself a piece of brass tubing with an inside diameter a little bit larger than the screw shank you are attempting to extract, to make your own "core drill bit". Using a miniature square file, you cut teeth in the end of the tubing, and then chuck it into a drill, being careful not to crush the tubing, then drill down and around the piece, which usually comes out readily once you drill past the screw depth. Then you dowel the hole (you might have to drill out to another size to accomodate a dowel) and redrill for a new screw.

Next time, use a stainless steel screw for your strap button. A lot of cheap hardware screws are crappy cast zinc and can break easily.

[thendrix]

Thanks for the help everybody. Its to far in to get a dremel or extractor to but i hadn't thought of a core drill. I will give that a try.

[Bruce Johnson]

Like John said, you need to make up a small core drill. Since you have access to a machine shop, that should be easy. Chuck up a piece of 1/4" dia steel rod stock (almost anything will do) in a lathe, face off the end, and drill the ID to a size slightly over the OD of the screw. Then use a small triangular file to cut a couple of teeth in the end. Chuck the core drill in a slow speed hand drill and gently drill out the broken screw. The core drill will follow the broken screw down into the wood and leave a clean 1/4" hole. I have an assortment of core drills that I've made up over the years to remove various sizes of broken screws in guitars.

You can fill the hole with standard birch dowel stock, or if you want to be really cool, you can chuck a piece of maple in your lathe and turn it to the right diameter for a nice sliding fit in the hole.

For strap button screws, I recommend that you get Self-Tapping Sheet Metal Screws in the right size, usually #6 x 1 1/4", with a Phillips Oval Head. Most hardware stores have them. The advantage of sheet metal screws is that they are hardened steel and are larger diameter at the root of the threads. They're zinc plated, but if you buff up the head, it'll look very close to chrome.

[thendrix]

Thanks for the help everybody. Made a core drill and it worked great. Cut the screw out, glued in a dowel on Friday and played a 4 hour gig with it on Saturday with no problems. Again, thanks.