Hi all, We are looking at a late model Fender Strat. (truss rod adjustment at head end) In the process of adjusting the truss rod, the tip of the allen wrench broke off in the adjusting nut, which as we all know is sunk about 1/4 down inside the neck. The access hole is 3/16 dia. so needless to say it is a challenge to see the little bugger, let alone finding a way to extract it. (none of the broken bit is sticking out, cannot grab it) and it seems to be wedged into the nut.

What i am thinking is to make a piloted counterbore (I am a retired machinist) and cut out the walnut plug that encircles the access hole, which will give me some room to hopefully "grab" onto the nut and back it out. Have any of you been here before? or Any other ideas or risks with my plan? I do not want to remove any part of the fretboard.

Much thanks for any and all ideas. suggestions. and comments.

Tags: fender, rod, truss

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Hi Hector.... I'm guessing the lack of response is because this has been a fairly well-traveled subject here, and boredom may have set-in ?:)

After you sign-in, go the the upper right-hand side of the main page (at the top) you'll find a "search" box... put in "broken truss rod" or something like that and you'll find a warehouse-full of past posts. 

Also, StewMac sells a complete ready-made (although quite pricey) kit to address the issue, but -since you're a machinist- you could probably replicate what they offer.

It is not a broken truss rod.

Yeah, well, it's a close cousin. the same advice applies. Search the site for others who've had trussrod nut problems and see what you get.  Best of luck. 

Maybe a magnet will help out? But maybe not. Depending on how clean the key broke off, you might be able to drill a hole in the broken off piece and use a remover for reamed screws to get a hold of it, then pull it out by grabbing onto that. Could be a fight though...

The stew mac tool and counterbore seem tricky to me because the nut is still there, so you cant use the rod to register it on centre. But if youre a machinist maybe you can come up with something to get around that. Cant say without seeing it, and Im no machinist.

I actually have done this before.  It's not that bad.  I was actually able to drill out the plug with a hand drill. (very carefully)  Then do the repair, then plug the hole with a plug I turned with the access hole already drilled in it.

It's not bad, just go slow and easy.

Here is a Flickr set of how I did it...

Some suggestions for some things to try before surgery:

Sometimes a light tapping with a punch and small hammer on the imbedded section will free a stuck hex wrench.

If you have the broken wrench and the missing piece isn't wedged into the adjusting nut too tightly - I have had some success putting a SMALL drop of high viscosity CA glue on the broken face of wrench, carefully inserting it into the adjustment hole and bonding the two pieces together.  A test fit to determine proper orientation prior to bonding is key - you want to mate the faces as close to the original orientation as possible to maximize bond area as a thick CA joint will not have much strength at all.  In this case, it will have to be done by feel.

Sometimes it will have just enough strength to back out the broken tip and extract it from the hole.  I will stress that you have to be very careful not to bond the wrench to the surrounding wood.  The glue should be no more than you can apply with a sharp pick or probe as run out is highly undesirable. 

Obviously, it doesn't work well with fastener or wrench remnants that are really stuck. 

These are what Id try first. So simple, and often that's best. I feel silly not having thought of it.

Hi again and thanks to all for thoughts and suggestions.

I decided to make that Counterbore which I used to bore down to the point where I could switch to a 3/8" drill. there is a thrust washer on top of the nut which I then removed. At this point I had much better access to the truss rod nut (with broken bit) I still could not get that broken piece out but there was enough of the hex recess exposed that I could use sideways pressure with my 1/8 hex wrench to back the nut out. Whew! about an hours work so far but we saved the neck. Live and learn right?


Nice work, Hector  .... perseverance triumphs once again!  


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