Metallics TP118SBC Screws 1/4-20 x 1 Btn Hx Pin TR MS 18 (100 pcs)

A standard hex key will not work. The TP118SBC has a button head with a hex socket that has a pin standing up in the center, so you need a pin-in-hex (hex pin) driver bit or key sized for a 1/4-20 button head fastener. That is the whole point of the design: without the matching pinned bit the screw cannot be backed out, which is why it gets used on panel covers, enclosures, and public-area fixtures.

It is a machine screw. The 1/4-20 thread is a uniform machine thread, so it needs a pre-tapped 1/4-20 hole, a 1/4-20 nut, or a threaded insert. It will not cut its own threads in sheet metal, so if you are fastening into unthreaded material you need a tapped hole or a nut on the back side.

Security against casual removal. On enclosure covers, panel fronts, and fixtures in public or tenant-accessible areas, a standard socket cap screw comes off with a common hex key from any toolbox. The pin-in-hex button head on the TP118SBC blocks that, so only someone with the pinned driver can open it. The low-profile button head also leaves less to grab with pliers than a hex head would.

Each pack is 100 pieces of the 1/4-20 x 1 inch pinned button head screw, so it is sized for repeat MRO work rather than a single fix. Buy the matching pin-in-hex driver at the same time if your crew does not already carry one, since the screws cannot be installed or removed with standard hex keys.