Metallics TSP17M 8 x 5/8 in. Pan Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

It will not sit flush. The TSP17M has a pan head, not a flat countersunk head, so it seats on top of the surface. The head measures 0.306 to 0.322 inch across and stands 0.105 to 0.115 inch above the work. If you are mounting something that has to come down flat over the screw, or sliding a plate past it, allow roughly an eighth of an inch of head height or pick a flat head instead.

These are rated to 39 lb-in minimum torsional strength and case hardened to Rockwell C28 to 38 from AISI 1016 to 1024 steel. That is enough for normal driving in sheet metal, but 39 lb-in is modest, and an impact driver or a high-torque drill set to full clutch will twist off a #8 easily once the screw bottoms out. Run them with a clutch or a screwgun with depth stop.

No. The TSP17M is listed as not Buy American compliant and not ARRA compliant, with multiple countries of origin. If your project carries a domestic sourcing clause, specify a domestically produced fastener instead.

The Metallics TSP17M is a Type A tapping screw, meaning it has a gimlet (sharp) point and a coarse thread, 15 threads per inch at the #8 diameter. That combination is made for thin sheet metal and soft materials where you drill or punch a pilot hole and the screw forms its own thread as it drives. It does not drill its own hole like a self-drilling point, and the coarse Type A thread is wider pitch than a Type AB, so it bites fast in light gauge stock but is not intended for thick steel.

A #2 Phillips bit. The recess is a Phillips drive with a 0.169 to 0.182 inch recess diameter and 0.108 inch depth, which is the standard #2 geometry. One bit covers the whole jar, so a crew running these all day only needs #2 tips on hand.

The TSP17M is carbon steel with a zinc plated finish. Zinc plating is a mild indoor corrosion coating, fine for dry interior electrical work, panel and enclosure mounting, duct and bracket work inside a building. For exterior, wet locations, or anywhere with chemical or coastal exposure, zinc plated steel will bloom and rust. Use stainless steel fasteners there instead.

Yes, these ship as a jar with a 1000-piece order minimum. There is no small blister pack of this size, so it suits an MRO stockroom or a contractor who goes through #8 x 5/8 sheet metal screws regularly rather than someone needing a handful. Other sizes and quantities can be requested.

Yes. Head and recess dimensions follow ASME B18.6.3-2013 and the thread follows ASME B18.6.4, with material to AISI 1016 to 1024. One caveat for spec writers: Metallics notes that dimensions for #9 diameter screws are independent of ASME B18.6.4, which does not affect this #8 size.

Working length is 5/8 inch under a pan head, and a Type A thread needs several threads engaged in the base material to hold. At 15 threads per inch you get roughly 9 threads over the full length, so after the thickness of whatever you are fastening through, plan on at least a quarter inch of the 5/8 going into the receiving stock. For stacking thicker assemblies, step up to a longer length.