Don’t know about helicoils I’m afraid. We’ve just had the age old problem of the bathroom door coming off on a very bumpy Devon road. As we were going to Ikea in Exeter (it was raining and we wanted to look at sofa beds) we raided their free bits and bobs section. The smallest dowels and screws worked a treat. Had to shorten the dowels and then hammer them in, good tight fit. Screw went in beautifully, now have rigid bathroom door. It’s not right that we have to do these mods but it worked.