10-16 x 1-1/4 in. Self-Drilling Metal, Zinc, Hex Head, Hex

10-16 x 1-1/4 in. Self-Drilling Metal, Zinc, Hex Head, Hex

You have probably seen them before.

The fellow that installed the ductwork for your furnace or air-conditioner probably used them. You may have even used them when putting something together that said on the box Some Assembly Required.

They are called self drilling screws and are they ever handy! A special point drills through the steel sheet metal quickly then the hardened steel threads self-tap the hole and pull everything together securely.

Most commonly known as "sheet metal screws" the Type A thread was designed to form or cut a mating thread in its mating material. Its symmetrical thread pattern with a 30° top and bottom angle offers good holding power in metals and plastics. This type of thread style is being used less in the woodworking industry due to the popularity of "Deep Thread" screws designed to offer optimum holding power. The length tolerance on a Type A screw is plus or minus 1/16 in. unlike woodscrews that have a +0 in./–1/16 in. to +0 in./–3/32 in. based on length.

Hex Washer Heads

This head style is usually found on larger fasteners such as lag screws. The six-sided hexagon-shaped head is nomrnlly driven with a socket bit. Some hex heads have serrations on the bearing surface that help bind the head to the wood. They are often used in bunk bed and chair production. Smaller hex heads are also used by some TV cabinet manufacturers to attach the rear panel to the cabinet.