repairscrews
Is it possible to fix a screw that has been stripped? It is not an uncommon problem to run into when you are into the DIY projects. I personally have come across this quite frequently. I would like a solution that would be permanent, and one that doesn't involve buying new screws. How do I do this?
I'm not asking how to remove them, as asked How to remove screws with stripped heads?. I want to know how to fix it.
You took the wind out of my sails with that last paragraph. I was going to suggest using a nut/bolt.
As far as it causing problems when the tabletop is lowered, you can recess the bolt head. Yeah, you could make the cavity in which the bolt will stay on the underside of the tabletop, but maybe you'll drill too far or crack/scratch the tabletop if you chisel it out. It could end badly... which is why you should instead house the bolt head on the top-side of the cross member.
Brown = table top
Black = underlying cross member
The one on the left is what you were talking about. The one on the right is what you want to do.
Also, use a washer under the bolt head, etc.
Most of the time you can chisel it out with a scratch awl and a utility knife. You will dull the blade of the knife, but that's why they are replaceable. I also would use my $2 awl, not the heirloom one with the rosewood handle.
Best Answer
Damaged screw-head
You can repair many small metal parts using a micro welder. Alternatively (and probably far more commonly) some people use a vice and a hammer to form the damaged head into a suitable shape for the next stage ...
You can re-cut a drive slot using a suitable tool. For slotted screws this would be a file intended for that purpose
Damaged screw-thread
For machine bolts, threads can be repaired using dies or helical inserts. I'm not aware of anything equivalent for things like wood-screws.
Standard practise
I admit I can't imagine any circumstances where I would not just drive to the store and buy a new screw (and probably a better screwdriver to match).