Broken HB base screw!!!

[ken]

Hello...

I got a HB pickup in for lengthening the hookup wire from a customer today.

One of the brass? base screws holding the screw coil onto the pickup is broken off in the coil bobbin. I want to extract this and put in a new screw. How do I do it without screwing up the bobbin?

Thank you,
Ken

[Spence]

Carefully drill it out from the top of the bobbin using a drill press.

[David Schwab]

I have a set of these... they come in real handy!

Screw Extractor Set (StewMac)

[Steve A.]

I have a set of these... they come in real handy!

Screw Extractor Set (StewMac)

That set looks great but I'm not sure how well it will work if the screw head has broken off.

I'd go along with Spence on this one, especially about using the drill press. If you don't have one you might check to see how much a machine shop or sheet metal shop would charge to use theirs for a just a minute or two (they will probably need to use the equipment themselves for insurance reasons). Without a drill press I have a hunch that the bit might tear up the coil wires.

I used to work in a sheet metal shop and for little projects like that it would take more time to write up the paperwork and ring it up so they'd usually just do it for free (but be sure to remember them at Christmas!)

Good luck to Ken on this!

Steve Ahola

[ken]

I fixed the broken screw...

I was going to try drilling it out, but I chickened out.

I did get it out OK, but my method was a bit weird...

The screw was broken off under the coil bobbin surface so I couldn't use a pliers, and my extractor wouldn't grab on the broken piece. However,
the broken screw was in a hole going through the pickup. So, I found a nail
with a diameter the same as the hole, ground the tip of the nail off flat, then dremeled a little round divot in the flat end of the nail to match the point of the screw so the nail wouldn't slip off the screw point.

Then I put a fine point on my soldering iron, turned it up to 800 degrees, flipped the coil over so the bottom end of the coil with the screw was toward me, and put the iron tip on the broken screw and waited. When the plastic started to melt and the screw started to loosen, I put my nail into the hole on the top side of the coil and gave it a quick shove. The screw popped out of the hole, I shaved down the melted glue on the bottom of the bobbin so the coil would sit flat, filled the hole with superglue so the new screw would hold OK, redrilled the hole, and reassembled the pickup. The screw held, the pickup looks like nothing happened, and the customer was happy.

Ken

[David Schwab]

That set looks great but I'm not sure how well it will work if the screw head has broken off.

That's what they are for. They have sharp teeth that grab onto the screw shaft so you can back it out.

I bought these to remove a tuning machine screw who's head had broken off.

[ken]

I tried my extractor, but the screw broke with a point on the end, not flat.
The extractor wouldn't grab the screw because the point stuck out further than the extractor teeth.

Ken

[SK66]

That was a great solution, maybe about the best option you had.
Funny how we don't "look further" than what we already know. I would have suggested small dia tubing with teeth cut in the end and drill press...basicly cuts a plug with the broken bit inside...I make these custom for myself as needed and since I learned this trick I've never tried the screw extractors shown above (better choice when they work I'd guess) nor would have I thought of what you did. I would NOT have drilled it out from the top.

[ken]

I use the tubing screw extractor to remove tuner screws broken off in headstocks. I was worried that if I used the 'cut plug' method, I would ruin the coil, which was OK at the time. The broken screw twisted apart and stretched and didn't break off flat like a regular screw would, so I didn't want to drill either.
If I drilled, the bit would 'bank off' the hard screw and drill the plastic, ruining the coil too.

Ken

[David Schwab]

The tubing idea works great, and sometimes better than the extractors. I've had some teeth break off the extractors also.

Sometimes you just have to be ingenious!