Metallics JDS171V 12 x 1 in. 5/16 Indented Hex Head Slotted Sharp Point Tapping Screws - Steel Zinc - Each

The JDS171V is a Type A tapping screw with a gimlet (sharp) point, which is the style meant for thin sheet metal, sheet metal boxes, and similar light-gauge work. The sharp point starts easily and forms its own thread as it drives, so in thin stock it can be driven without pre-drilling. In heavier material you still want a pilot hole, because a Type A thread is a coarse 11 threads per inch and relies on the metal being thin enough to deflect and form around it.

Either works. The head is an indented hex with a slot cut across it, so it takes a 5/16 nut driver or socket (head width measures 0.305 to 0.312 inch, 0.34 inch across the corners) and the slot gives you a flat-blade backup when you cannot get a driver square on the head. The slot runs 0.056 to 0.067 inch wide and 0.077 to 0.093 inch deep, so use a cabinet-tip blade rather than a fat general-purpose one.

The JDS171V is flagged compliant for both Buy American and ARRA, which is what a government, school district, or federally funded project submittal normally asks for. Country of origin is listed as multiple, so if your spec requires a single named origin on the certificate, that needs confirming for the lot you receive.

These ship as a 500-count jar, and 500 is the order minimum. If you need a different size or a different pack count, Metallics makes other diameters and lengths in the JDS series on request.

The JDS171V is AISI 1016-1024 carbon steel with a zinc plating. Zinc is a dry-location and light-duty finish, fine for interior boxes, enclosures, straps, and panel work. For sustained wet, washdown, or exterior exposure, step up to a stainless or hot dip galvanized tapping screw instead, because the plating on a carbon steel screw is the only thing standing between the shank and corrosion.

Minimum torsional strength on the JDS171V is 83 lb-in, with the screw case hardened to Rockwell C28-38. That is the drive torque ceiling, not a service load rating. On an impact driver it is easy to exceed, so for thin sheet metal set the clutch low and stop as soon as the head seats.

Yes, it is an indented hex washer head. The washer outside diameter runs 0.398 to 0.432 inch at 0.022 to 0.039 inch thick, and overall head height is 0.139 to 0.155 inch. That flange spreads the clamp load so the screw will not pull through light-gauge sheet, which is why no separate washer is needed on most box and strap work.

Head and body dimensions follow ASME B18.6.3-2010 and the thread follows ASME B18.6.4, so a #12 from this series interchanges with any other screw built to those standards. One caveat Metallics states: dimensions for the #9 diameter in the JDS line fall outside ASME B18.6.4. That does not affect the #12 x 1 inch.

A jar of 500 comes in at 5 lbs, in a container measuring 7.25 inches high by 4.5 by 4.5 inches. That size sits fine on a standard van shelf or gang box tray.