screwswood
I have an Ikea chest of drawers with metal rollers that allow me to slide the drawers in and out.
One of the drawer’s metal roller screws has popped off due the weight of the contents of a shelf and when I tried to rescew it back in, the screw just spins around. What is the best way to re-thread this hole? Would wood filler be strong enough?
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.
I would say the optimal screw hole shape that will allow the maximum amount of torque to be applied, would be no hole.
Removing material from the head of the screw; no matter what shape, will weaken the screw slightly. The only way to maintain the full strength of the screw; and therefore achieve maximum torque, is to not remove any material. So a hex head screw (not to be confused with a hex drive screw), would allow for maximum torque.
Best Answer
Remove the castor, get some PL premium, glue it back on.
Or just get some small pieces of wood (wooden match sticks - minus the head - and jamb those into the hole with or without glue, cut the ends of the wood pieces off flush and screw into that mess.