Amp cabinet repair advice sought.

ElectroDan

Hey guys before I go wading in.

A few of the screws holding the (ply) speaker baffle to the cab of my H&K Duotone, have stripped their threads. There are longer ones on the sides. and shorter ones that go through the bottom of the baffle from the back into the lower lip on the cab.

Filling and re-drilling is something that is not going to work for a man with such a lack of resources and talent as I.

So I'm thinking of wedging some slices of matchstick in the holes, but I'm wondering is a dab of wood glue a good idea too.

Got to get it locked in there tight. It was farting and barking something terrible.

Thanks

ICBM

The best method is the simplest and does not need tools - put wood glue in the holes, pack as many matchsticks or tooth picks in as you can and break them off flush, then put it back together immediately with the glue still wet - no drilling. Don't overtighten them, just yet - firmly enough to pull the baffle tight but not enough to chew up the matchsticks - you can crank them up after the glue has set.

The glue and matchsticks will be compressed by the screw and form a very strong cast-in composite thread in the hole. This is actually stronger than the 'proper' method of drilling out and dowelling because it will grip the remains of the old damaged threads, and by not re-drilling, you will produce a much stronger bond.

Really!

ElectroDan

Thanks for the reply @ICBM

I was only going to put a few bits of match stick in, but you reckon to pack it tight eh!

One more question though if I may. Will the wood glue bond to the screw making it impossible to ever remove them?

ICBM

ElectroDan said:

I was only going to put a few bits of match stick in, but you reckon to pack it tight eh!

Yes, pack it tight. Don't worry, you won't actually be able to get it really that tight, and it will crush down to fit.

ElectroDan said:

One more question though if I may. Will the wood glue bond to the screw making it impossible to ever remove them?

No, wood glue doesn't bond well to metal.

ElectroDan

Awesome. You must be getting sick of wisdom's.

Thanks again and Merry Christmas.

ecc83

Stock dowelling is not so good as you are screwing along the grain.

Either get the kit for a "crossgrain plug cutter" or bore the panel out to take a dowel across the hole*

But in this case go with ICBM!

*Standard practice for pipe organ stop slides.

Dave..

ElectroDan

Thanks @ecc83

I will be gluing and screwing later today (if the Man flu will allow). I have learned something new again, as I never knew that a dowel should be cross grain.

Interestingly, the reverb was intermittent on the amp too. I assumed the plug sockets had lifted from the board, so bought a new cable with right angle jacks to take the stress off them. When I opened the chassis though the joints were good. It took me a while to work out that what I'd assumed was an omitted resistor, was rattling around trying to short something out. It was perfectly formed and clipped, but had soldered on the very bottom of the leg, so that it had been standing proud of the board.

Don't know how it passed the notoriously efficient German QC procedures.