Metallics JTSF43 10 x 1-3/4 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

The JTSF43 is a #10 x 1-3/4 in. Type A tapping screw with a gimlet point. The gimlet point and coarse 12 threads per inch let it cut its own thread in sheet metal, thin steel, and similar soft materials without a pre-tapped hole. Head is flat with a Phillips recess, so it countersinks flush.

Size the countersink to the head: the flat head measures 0.333 to 0.362 in. across with a head height of 0.098 to 0.116 in. Open the hole in the sheet or plate to roughly 0.362 in. at the surface so the 82 degree head pulls down level with the material.

They are rated to a 48 lb-in minimum torsional strength and case hardened to Rockwell C28-38 from AISI 1016-1024 steel. That is enough for normal sheet metal work, but an impact driver can exceed 48 lb-in easily. Drive with a clutch-equipped drill on a moderate setting and stop once the head seats.

A #2 Phillips bit. The recess is 0.198 in. diameter, 0.124 in. deep, with a 0.032 in. slot width, which is the standard #2 geometry. Running a #1 or #3 will cam out and chew the recess.

These are carbon steel with a zinc plating, which handles indoor and protected environments. Zinc plate is not a marine or sustained-wet finish, so for exterior exposure, coastal air, or wash-down areas step up to stainless.

Yes. The JTSF43 is built to ASME B18.6.4-1998 for dimensions, with threads to ASME B18.6.4 and steel to AISI 1016-1024. That means head, recess, and thread geometry interchange with any other B18.6.4 #10 Type A screw on a spec'd job.

Match the pilot to the screw's gaging diameter of 0.313 in. by drilling under it, so the gimlet point can form thread and the flank has material to bite. In thin sheet the point will often start on its own; in heavier stock a pilot prevents the 48 lb-in torsional limit from being reached before the head seats.

Type A, like the JTSF43, has a gimlet point that taps its own thread but does not drill. It suits thin sheet metal, sheet steel boxes, and soft materials where the point can pierce or a small pilot is easy. If you are fastening through heavier gauge steel or structural plate, use a self-drilling (Type TEK) screw instead, which cuts its own hole first.

They ship in a jar of 100, and 100 count is the order minimum. Jar weight runs about 0.95 lbs.