Old Tub with special over flow plate screws?

Question

Had to snake a vintage tub (1950s) took over flow plate off. All was fine until reassembling plate cover. Special screws are about 3/4 inch long with a square tip did not tighten up. Hardware and Homecenters offer replacement cover plates with bolts that are standard in design and an inch too long. The overflow plate bracket has no holes to accept bolts of the length Cast Iron tub / galvanized plumbing is ok in other respects. No service panel - area above tub is tiled.

Thanks for the reply - the tub has no markings as to who made it / the tip of the screws are not threaded so tap/ dye would not help, this setup must have used some form of friction between the cover plate / screw and plumbing wall the screw tip touches. Another solution that might work is replacing this trip lever assembly setup ( the working end has a brass cylinder in the overflow pipe ) with a toe stop stopper system visible right at the tub drain. securing the cover plate may still be an issue though since again there is no threaded hole in existing plumbing, would hate to attempt to tap that since starting hole for tapping exactly where needed is a bit hard - it's not like you can clamp this down to drill press

Answer 1

try cuting the new screws"wont hurt" you might have to tap them "tap & dye set"but if that don,t work look up the tub name on line and see if they are still around and if not let me know and i,ll find another way for you,,,,,,just don,t bang up the tub trying.

Answer 2

brake a toothpick in half and insert it into the hole.