Metallics FMPUC4M Screws 8-32 x 1/4 FH PH Undercut M/S (1000 pcs)

At 1/4 inch, these are short fasteners meant for thin material, metal boxes, plates, brackets and panels where the tapped hole or the stack-up is only a fraction of an inch thick. If you are reaching through a raised cover, a plaster ring or any spacer, 1/4 inch will not pick up the threads and you want a longer 8-32 machine screw instead.

An undercut flat head has a shortened head height, which leaves more of the 1/4 inch length as usable thread. On a screw this short that matters: with a standard 82 degree flat head, much of the length is consumed by the head taper and you get very little thread engagement. The undercut version lets a 1/4 inch screw still bite properly in a thin tapped part while sitting flush in the countersink.

Flush, provided the hole is countersunk. This is a flat head screw, so it needs a chamfered or countersunk seat to pull down level with the surface. In a plain drilled hole with no countersink the head will stand proud. If you need a screw that seats on a flat surface instead, use a pan head or round head 8-32 rather than this flat head.

Machine screw. The M/S in the Metallics FMPUC4M description means machine screw, so it has straight, uniform 8-32 threads and requires a pre-tapped hole or a nut. It will not form its own thread in sheet metal the way a self-tapping or sheet metal screw does.

They ship 1000 pieces per box, which is bulk-pack quantity for an MRO crib or an electrical shop that standardizes on 8-32 hardware across a facility. One carton covers a lot of device, plate and panel work rather than reordering small packs per job.