Decision time... best way to deal with sheared neck screws?

[Stub Mandrel]

For the last few decades a minor misalignment of the bolt on neck of my mid-70s Epiphone acoustic has annoyed me. But two of the screws were immovable and rounded out.

 

Today I bought a set of removal bits, but unfortunately the two screws sheared off... from the look of the two that unscrewed normally, they have rusted and expanded into the wood

 

I will have to try and drill them out. This might not succeed. I'm wondering if it might be better to make and use a core drill and fit a pair of wooden plugs or even threaded inserts.

 

The good news is that a thin slip of card seems to be enough to get the neck pointing the right way.

 

Any suggestions for the best way forward?

 

 

[skankdelvar]

Far be it from an idiot like me to offer advice to a man of your engineering calibre but I'd imagine it would be a complete bastard trying to centre up a tiny drill on those screws, even with a drill press. Coring them out then re-drilling for a dowel might be a less exacting task.

 

As for threaded inserts, well, are you going to be taking the neck on and off with any degree of frequency? If not, why bother? The 'simple' repair will hopefully last you for another 40 years 

Edited February 9, 2022 by skankdelvar

[AndyTravis]

Yeah, go around and dowel.

 

or diagonal holes either side of each sheared screw - needlenose pliers…then dowel.

[hiram.k.hackenbacker]

I've tried this on a pair of similarly sized screws that had sheared off (not a bass I hasten to add, but hinge screws on fitted wardrobe surrounds).

As enticing and seemingly simple as you might think it would be, getting the b**tards out even if you drill the screws correctly, may not be the easy part.

As advised above, I would go around, especially on a guitar neck. Even better, get David Wilson to do it for you.

Good luck.

[AndyTravis]

Got a dremmel?

 

not sure if it’d work.

 

obviously screws are made of butter…

 

carve a slot into the “head” of what’s left. Flat head screwdriver…get it started out and then back it out…

[ezbass]

I had this on a PRS strap button screw. The guy at Chandler’s said his preferred method was to drill a hole in the screw and then tap in a small, tapered, triangular file, then just unscrew it. Didn’t see him do it, but he got it out.

Edited February 10, 2022 by ezbass

[Stub Mandrel]

Thanks for the observations.

 

These aren't going anywhere unless drilled out, but I shall core drill and dowel rather than trying to drill them directly, which would still leave an oversize hole. I've just ordered a set of cheap plug drills off Prime, I can use a larger one to cut plugs out of soke mahogany I have to fill the hole made with the 6mm which seems right for working around 5mm screws.

 

Any glue recommendations?

 

The guitar is very special to me, I found it in a secondhand shop in 1983, and rang up my mum to ask if she would pay for it as my 21st birthday present. It's big, loud jumbo, still with paper S/N and maker's label inside.

[Stub Mandrel]

12 minutes ago, ezbass said:

I had this on a PRS strap button screw. The guy at Chandler’s said his preferred method was to drill a hole in the screw and then tap in a small, tapered, triangular file, then just unscrew it. Didn’t see the, do it, but he got it out.

 

The removal tool I used essentially works that way - used in a pistol drill run in reverse. They drill a pilot hole in the head, then a pair of serrated flutes bite into the sides of the hole, but the screws just sheared off they are totally locked.

[Twincam]

1 minute ago, Stub Mandrel said:

Thanks for the observations.

 

These aren't going anywhere unless drilled out, but I shall core drill and dowel rather than trying to drill them directly, which would still leave an oversize hole. I've just ordered a set of cheap plug drills off Prime, I can use a larger one to cut plugs out of soke mahogany I have to fill the hole made with the 6mm which seems right for working around 5mm screws.

 

Any glue recommendations?

 

The guitar is very special to me, I found it in a secondhand shop in 1983, and rang up my mum to ask if she would pay for it as my 21st birthday present. It's big, loud jumbo, still with paper S/N and maker's label inside.

 

Titebond original red.

Repaired headstock/neck breaks and other repairs on wood and it's always lasted.

I've even thinned it down and injected it into wood cracks. And it made a strong bond. 

 

Don't bother with there other wood glues. Original is the best. 

[PaulThePlug]

I'd be going Pilot Hole and extractor...

https://www.screwfix.com/p/bolt-extractor-set-5-pieces/1112V?tc=FT3&ds_kid=92700055262507123&ds_rl=1244066&gclid=CjwKCAiA6Y2QBhAtEiwAGHybPazEp068303QkjuS_Ch6ar-IGrnEJdjztQXAJgKVJpYd5f1XZDVqthoCfxgQAvD_BwE&gclsrc=aw.ds#product_additional_details_container

The screw is in wood... not a rusted bolr bolt in an engine casing, or broken 'zorst stud... £3.50 is worth a go!

 

Tang of a file works in soft brass... not sure about steel screw.

 

Core-ing would be my last resort...

Edited February 9, 2022 by PaulThePlug

[fleabag]

Plenty of good suggestions, especially the triangular butt of a file or what not.  This is the cheap version of an Easy Out tool.

 

If you're only going to do this once, then those methods will work as long as you can drill a decent hole in the screw shaft.

 

Just for referebce, the photo is my own easy outs,  and you do the same method as posted above.  Drill a hole suitable for the size of the Easy Out.  You'll need a smaller one than i have here.

 

Tap the Easy Out bit down into the drilled hole and wind it it back out, either with the proper tool, like those that come with a tap and die set, or some Mole Grips.

 

 

 

 

[songofthewind]

Aldi sometimes have those easy-out things, a set for very little money. Try their website.

[3below]

Much good advice previously. Easy out first if getting a hole in the screw is possible. If this proves resistant you could try drilling holes around the screws  with a 1mm / 1.5mm drill bit (they break very easily) to reduce the grip on the screw and then try the easy out again. If this fails try a partial core drilling, just deep enough to let you grip the screw with pliers or cutters. Finally if all else fails, use the full core drill. It is all fixable

[Geek99]

I must say that I like @AndyTravis suggestion; that’s what I’d do 

[AndyTravis]

3 minutes ago, Geek99 said:

I must say that I like @AndyTravis suggestion; that’s what I’d do 

Disclaimer - if it goes wrong; you ain’t seen me, right?

[Reggaebass]

Being a carpenter I’ve come across this many times, the normal practice is to cut a slot in the broken screw and ease it out with a slotted screwdriver, you can make it easier by drilling 2.5mm holes around the screw but you would have to plug the bigger hole after,  or failing that it’s an extraction kit 

[fleabag]

I'm trying to think how one would cut a slot in those screws... presumably with a hacksaw. But even a mini hacksaw needs enough space for forward and backwards motion, and with the screws flush to the body, i dont see how that could be done. 

 

Maybe a dremel  with a hard cutting disc ?  This would negate the need to have space for a hacksaw to work

Edited February 10, 2022 by fleabag

[Reggaebass]

29 minutes ago, fleabag said:

Maybe a dremel  with a hard cutting disc

That’s the way I would go fb 👍

[fleabag]

That sounds like a plan 

 

[AndyTravis]

Save any dust or bits of wood too 😉

[Count Bassy]

What ever method you use to turn it, it may be worth sticking a soldering iron on it first to expand it a bit, and then let it cool down again. This can help break the 'seal' between the screw and the wood. Alternatively, once to have a dimple in the end put a centre punch in it and wack it with a hammer. - again only enough to break the seal, you'll still need to turn it.

 

A word of warning ion the scree extractors, thay are hard and can snap - leaving you with a piece of hardened steel in the end of the screw.

[Geek99]

5 hours ago, fleabag said:

I'm trying to think how one would cut a slot in those screws... presumably with a hacksaw. But even a mini hacksaw needs enough space for forward and backwards motion, and with the screws flush to the body, i dont see how that could be done. 

 

Maybe a dremel  with a hard cutting disc ?  This would negate the need to have space for a hacksaw to work

Isn’t that exactly what Andytravis says above ? 

 

Got a dremmel?
 

    …

    carve a slot into the “head” of what’s left. Flat head screwdriver…get it started out and then back it out…
 
 

[tegs07]

Personally I would give the dremel method to cut a slot in the broken screw a try first, failing that go round the screw in circles with the dremel and plug with a dowel. I’ve used the second method to remove broken machine head screws a few times. It does leave a largish hole to plug. These guys are a useful resource:

 

https://plugitwood.co.uk/collections/plugs/products/maple-flat-cross-grain-plugs?variant=31721128820772

[Stub Mandrel]

On 09/02/2022 at 23:46, PaulThePlug said:

I'd be going Pilot Hole and extractor...

https://www.screwfix.com/p/bolt-extractor-set-5-pieces/1112V?tc=FT3&ds_kid=92700055262507123&ds_rl=1244066&gclid=CjwKCAiA6Y2QBhAtEiwAGHybPazEp068303QkjuS_Ch6ar-IGrnEJdjztQXAJgKVJpYd5f1XZDVqthoCfxgQAvD_BwE&gclsrc=aw.ds#product_additional_details_container

The screw is in wood... not a rusted bolr bolt in an engine casing, or broken 'zorst stud... £3.50 is worth a go!

 

Tang of a file works in soft brass... not sure about steel screw.

 

Core-ing would be my last resort...

 

I've already tried an extractor, the remaining bits are only about 4mm in the core, too small for one. They are as stuck as any fixing I've vome across, one of the sheared leaving a 1cm stub I was able to get a huge combination pliers on to. It just sheared off again.

[Stub Mandrel]

4 hours ago, Geek99 said:

Isn’t that exactly what Andytravis says above ? 

 

Got a dremmel?
 

    …

    carve a slot into the “head” of what’s left. Flat head screwdriver…get it started out and then back it out…
 
 

 

The trouble with a dremel is that the screw core is only 4mm. A 1.4mm slot would only have 1.3mm of steel either side and I would have to use a small screwdriver. No way it could generate the torque needed - these are stuck fast enough to shear the full screws.

 

I have a very good pillar drill and can hold the neck in a macine vice (leather pad for protection). I can probably drill out the screw, but will still have an oversize hole that needs to be plugged.  It all comes down to what size of plug is best.

 

I good news, I have found the packet of D'addarios I bought in preparation 😀