Metallics JTEKD30SS 12 x 3 in. 5/16 Indented Hex Head Self-Drilling & Tapping Screws with Washer - #3 Drill Point - 410 Stainless Steel - Each

It is a #12 diameter screw, 3 inches long, with 14 threads per inch to SAE J78-2013. The full 3 inches gives you reach through insulation, furring, or a spacer before the point hits the steel, but remember the drill point has to pass completely through the panel before the threads engage, so count your total stack-up against the 3 inch length.

No pilot hole within the rated range. The JTEKD30SS is a Type BSD self-drilling and tapping screw, so the drill point cuts the hole and the 14 TPI thread forms its own mating thread in one pass through panel of 0.110 to 0.210 inch. Pre-drilling only comes into play above that thickness.

The JTEKD30SS is made from 410 stainless steel, a hardenable martensitic grade. That is what lets it be heat treated to Rockwell C38-46 so the point can actually drill steel, which 300-series stainless cannot do. It gives better corrosion resistance than plain carbon steel for damp interior and sheltered exterior work, but 410 is not the choice for coastal salt spray or chemical exposure, where a 300-series or bi-metal fastener is the right call.

A washer is integral to the head. Its outside diameter runs 0.398 to 0.432 inch with a thickness of 0.022 to 0.039 inch, which spreads the clamp load over thin panel and strut. It is a bare metal washer, not a bonded EPDM seal, so if you are fastening roofing or any weather-exposed panel that must shed water, plan on a separate sealing washer.

The JTEKD30SS carries ARRA compliant and Buy American compliant flags in its product data, with country of origin listed as China. On a federally funded project where a domestic-melt or domestic-manufacture clause applies, verify which flag your specification actually invokes before submitting.

Minimum torsional strength on the JTEKD30SS is 92 lb-in, built to ASME B18.6.3-2010 dimensional requirements. Set your screw gun clutch below that. Metallics notes minimum torques are the same for stainless and steel self-drill screws, and drill time runs about 2.5 seconds on a 1 mm plate, so if the point is spinning longer than that you are burning the tip rather than cutting.

These ship in a jar, with a minimum order of 100 count at about 2.29 lbs for the container. That is a shop-shelf quantity rather than a bulk carton, which suits a service truck or an MRO crib stocking one size of #12 x 3 self-drill.