Maybe by moving the metal like a crater with a punch, before drill a very small hole ?
Than use a screw instead of taping ?

I've had success in the past using roll form taps on PC case sheet metal. Perhaps take a look at those. No material loss from drilling means more metal to thread.

nali wrote on 2026-01-08, 21:06:

Maybe by moving the metal like a crater with a punch, before drill a very small hole ?
Than use a screw instead of taping ?

this is what I would do, use a sheet metal screw instead of the usual 6-32 machine screw

Can’t you just put a hole where needed and use a correctly threaded nut behind said hole?

Rivnuts

nali wrote on 2026-01-08, 21:06:

Maybe by moving the metal like a crater with a punch, before drill a very small hole ?
Than use a screw instead of taping ?

StriderTR wrote on 2026-01-08, 22:55:

I've had success in the past using roll form taps on PC case sheet metal. Perhaps take a look at those. No material loss from drilling means more metal to thread.

Roll form taps are interesting, I did not know about these. Using one of those in a hole like described by Nali could work.
Normally roll forming taps require an exact (large) hole size, but in this case the excess material can be pushed out of the way, forming a flanged hole.

maxtherabbit wrote on 2026-01-08, 23:15:

...
this is what I would do, use a sheet metal screw instead of the usual 6-32 machine screw

Even though I am a metrics guy, for some reason the UNC #6-32 screws are part of the PC tinkering experience 😉 so I will try to keep those in. That being said, having a cover actually screws in place is the most important goal.

paradigital wrote on 2026-01-09, 06:19:

Can’t you just put a hole where needed and use a correctly threaded nut behind said hole?

Unless I can somehow fixate the nuts, it will spin, making it impossible to screw or unscrew (the nuts will be inaccessible once the cover is on).

NeoG_ wrote on 2026-01-09, 07:18:

Rivnuts

Yes, UNC #6-32 rivnuts exist! This will be my plan B.

Since metric cutting taps are the standard here, I will need to order a (fluteless) roll forming tap from abroad. It will probably take a few weeks to arrive. In the meanwhile I will also order some rivnuts (+ 6-32 bolts, since I do not have a rivnut tool), I think those can be handy to repair stripped threads.

I will keep you posted. Thanks for the suggestions!

I just remembered those things exist.
I think they are easy to find, maybe with car parts.
In case the hole is too far from an edge, at least it's wide enough it should hold in place when glued by some epoxy. Maybe cutting them in half before.

Last week, I finally got around to fixing my AT case.
Initially I tried to obtain UNC #6-32 rivnuts, but I ended up using M4 instead.
It turned out great an I would definitely recommend them. The manual tool will set you back about €5 and is easy to source.
Here are some pictures of the end result:

As an added bonus, I also found this, under the EPA sticker 😁
I just love the idea idea of putting a MHz display into my 486

Looks good. Rivnuts are the way to go. You can get all different kinds too.. open end, closed end, flush mount, etc. With thin cheap sheet metal, tapping will only get you one or two threads at best -- which of course will strip or cross-thread easily.

For that EnergyStar logo, I think backlighting it with a green LED would be pretty awesome as well. (if the lettering has transparency) The case isn't really from an era where MHz displays were useful anymore.