Metallics JTSF25 10 x 1/2 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

The Metallics JTSF25 is a Type A tapping screw with a gimlet point, so it drills into and forms its own thread in thin sheet material as it drives. The widely spaced thread (12 threads per inch at a #10 diameter) is what lets it bite in thin gauge metal. It is a self-tapping screw, not a machine screw, so no tapped hole or nut is needed, just a pilot hole in the stock.

Flat head is a countersunk design, so it finishes flush when driven into a countersunk or dimpled hole. Head height runs 0.098 to 0.116 inch and head width 0.333 to 0.362 inch, which is the countersink diameter you need to clear for a flush finish. If the plate is not countersunk, the head will stand above the surface by roughly that head height.

No. The JTSF25 screws are not Buy American compliant and are not ARRA compliant, with multiple countries of origin. If your project has domestic sourcing requirements, you need a domestically manufactured fastener instead.

A #2 Phillips bit is the correct driver. The recess measures 0.198 inch in diameter and 0.124 inch deep, so a #1 bit will cam out and a #3 will not seat. With 48 lb-in minimum torsional strength, a #2 bit in a clutched driver is the safe combination for driving these without snapping heads.

Because it is a flat countersunk head, the 1/2 inch length is measured overall including the head, so the usable thread below the surface is less than a half inch. That makes the JTSF25 a screw for thin stock, sheet metal boxes, straps, and plate-to-sheet attachments rather than for anything needing deep thread engagement. For thicker build-ups, step up to a longer length in the same JTSF series.

These are carbon steel screws with a zinc plated finish. Zinc plating handles indoor and normally dry conditions well, but it is a sacrificial coating, not stainless, so in wet exterior, coastal, or chemically aggressive locations it will eventually corrode. For those openings specify a stainless fastener instead.

They ship in a jar of 100, and 100 is the order minimum. The jar weighs 0.35 lbs. Other sizes and quantities in the series are available by request.

The JTSF25 is built to ASME B18.6.4-1998 for dimensions and ASME B18.6.4 for the thread, with steel per AISI 1016-1024 and a case hardness of Rockwell C28-38. Note that for #9 diameter screws in this series the dimensions fall outside ASME B18.6.4; the #10 covered here is to standard.

Yes, that is exactly the intended use. Metallics lists the JTSF series for the electrical, plumbing, and heating and air conditioning trades, which is why they are stocked as an electrical fastener. A #10 x 1/2 inch flat head zinc tapping screw is the common choice for fastening straps, clips, and thin brackets to sheet metal.