I've got some alloy hinges which need to be threaded to take an M6 bolt. They are countersunk at the moment so I would have to tig the holes and redrill & tap but I am a little concerned that they might be weakened as a result.

It then occurred to me that a steel hank bush or something similar could be pressed into the countersunk side, allowing a stronger M6 thread.

Does anyone know of something suitable?
Rescued attachment Hinge.jpg

What size are the holes and countersinking to start off with. Could you not use M6 cap heads and use the existing countersinking? I probs dont understand the application enough to advise. Dont recall fitting doors to mine

Could you not drill and tap them M8?

rivnut??

Mike you only have to ask...
I'm not a million miles away you know.
Get some measurements and I'll turn you up some stainless threaded inserts.
Ill come round at the w-end if you like and we can have a measure up.

Brian - you are a STAR

Just to cover the points mentioned...

The bolts need to come in from the back of the hinge ie the opposite side to the c/sink.

Drilling out to M8 will probably take all the meat out of the hole and make it too fragile.

I did think of a rivnut but the hole would be too large (same reasons as above)

Thanks for the input guys - looks like its BKLOCO to the rescue again!

Have you thought about using a spoke nipple? If you can get them in 6mm they would probably be suitable

I like your lateral thinking Rusty but I can only find small (around 2mm) spoke nipples. Nice idea though