Replacement screws/armrest repair

[LeeF]

Where can I find replacements for the three screws that hold the center armrest to the hinge? When removing the armrest for re-covering, the original screws were too tight and had to be drilled out. I could not find replacements at a hardware store. They appear to be Phillips head self-tapping, longer than 1/2" but shorter than 3/4", maybe slightly bigger than an 8. I cannot locate a diagram that gives the screw specs, either.