Advice please - oops

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old_picker
Blackwood
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Advice please - oops

Post by old_picker » Wed Sep 23, 2015 12:56 pm

Image
Not quite sure what to do here - the screw is snapped off just below the surface - diamater is 2.7mm x 25mm long - too big for the stewmac doo hickie - blue tape marks the back of the bridge - is there a way to retrieve it or am I wasting my time ?

Fitted quite a few of these bridges and never had this happen before - Had a test string up prior to finishing and on removing the bridge got 3 out out 4 you can see on the left protested but yielded in the end and 5 snapped off as soon as pressure applied. Screws seem to be smaller and softer than previously and I remember them going in pretty tight. The timber is myrtle and pretty hard and dense.

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rocket
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Re: Advice please - oops

Post by rocket » Wed Sep 23, 2015 2:21 pm

Maybe try an, easy out,, first if that fails maybe a plug cutter?

Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back

www.octiganguitars.com

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Mark McLean
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Re: Advice please - oops

Post by Mark McLean » Wed Sep 23, 2015 4:36 pm

I have had success with using a dremel or drill bit to score a groove across the broken screw so that you can get a screwdriver onto it.

dshaker
Myrtle
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Re: Advice please - oops

Post by dshaker » Thu Sep 24, 2015 6:05 am

Most largish hardware stores, at least in the States, have screw-extractors somewhere near the drill bits. A complete set includes a drill bit to put a small hole down the middle of the screw and a reverse-threaded thingie that goes into the hole you just made and turns the screw in an appropriate manner to remove it. I've never used one, but that's what I would try. And I think I'd make something to hold the drill bit in the right location above the screw, lest it skittered off the screw head and started to booger up the wood.

No experience here, though. That's just what I would try.
-Doug Shaker

old_picker
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Re: Advice please - oops

Post by old_picker » Thu Sep 24, 2015 9:41 am

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6.35mm [1/4"] od brass tube with some points filed into the bottom which makes a nice mini hole saw - or i guess plug cutter - when i got to depth the plug just broke off and pulled out screw and all. A neat trick that I had seen years ago somewhere on the interwebz but always discounted because I felt that putting that fine brass tube into the drill press chuck would undoubtedly distort the tube and throw it off center making it unusable. Necessity is the mother of invention so I thought if I wrapped a 25mm length of hardwood dowel in masking tape and forced it down the top of my improvised mini hole saw it would stabilise things a bit. Perfect - I chucked it in the drill press and it ran true enough. I slowly worked it through the tough figured myrtle taking heed to let it cool every 5 mm or so. I re sharpened it about halfway down. I was almost to depth and pulled up for a cooling spell and to my amazement I was left with a very neat 1/4" hole. I quickly filled it with a plug cut from a myrtle offcut. I had thought that I may have a lot of trouble prising that plug out of its hole but luckily not the case.

Many thanks to those who have offered advice. For those of you who don't know me this is not the first guitar I have built and in fact I've built quite a few. I would have thought by now that I should have learnt to lubricate my screws EVERY time.

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kiwigeo
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Re: Advice please - oops

Post by kiwigeo » Thu Sep 24, 2015 11:52 am

That's pretty much how we handle a twisted off drill string in the oil patch......a nice little miniature overshot/milling assembly :D
Martin

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rocket
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Re: Advice please - oops

Post by rocket » Thu Sep 24, 2015 12:35 pm

Nice work Picker, good save.
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back

www.octiganguitars.com

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