Metallics TP219SBC Screws 1/4-20 x 1-1/4 Btn Star Pin TR MS (100 pcs)

The TP219SBC is a star (Torx-style) drive with a center pin in the recess, so a standard Torx bit will not seat. You need a pin-in-star (Torx-Plus tamper resistant style) bit with a hole drilled in the tip to clear the pin. That pin is the whole point of the fastener: it keeps a common Torx or hex driver out of the head once the plate or cover is installed.

It is a machine screw, 1/4-20 x 1-1/4 inch. A 1/4-20 machine thread needs a mating tapped hole or a nut, so it does not cut its own thread into sheet metal. If you are fastening into unthreaded metal you will need to tap the hole to 1/4-20 or back it up with a nut.

At 1-1/4 inch of 1/4-20 thread, this screw is sized for stacking through a cover plus a backing member or into a tapped boss. On a thin cover plate over a shallow box the excess length will bottom out or protrude behind the nut, so measure your total grip (cover thickness plus the depth of tapped material) before committing. Where you only need to pick up a plate and a thin flange, a shorter 1/4-20 pin-star button head is the better call.

The button head sits as a low, rounded dome above the surface rather than pulling flush, so it does not need a countersunk or chamfered hole, which matters on thin covers and enclosure flanges that cannot be countersunk. Combined with the pinned star recess, there is also very little edge for someone to grab with pliers or a screwdriver tip.

Each pack holds 100 screws of the 1/4-20 x 1-1/4 inch button head pin-star fastener. For MRO and institutional buyers standardizing tamper resistant hardware across a facility, that is enough to cover a run of covers or plates on one thread size and one driver bit.