Metallics DS835M 12 x 3 in. 5/16 Indented Hex Head Slotted Sharp Point Tapping Screws - Steel Zinc - Each

The Metallics DS835M is a Type A tapping screw with a gimlet (sharp) point and 11 threads per inch. Type A with a sharp point is the coarse-thread, spaced-thread style meant for thin sheet metal, plus common use in wood and composition board where the point can start its own hole. It is not a machine screw, so it is not intended to run into a tapped hole or a nut.

Dimensions follow ASME B18.6.3-2010 and the threads follow ASME B18.6.4. The steel is AISI 1016 to 1024, case hardened to Rockwell C28-38, with a minimum torsional strength of 83 lb-in. That torsional figure is the number to watch if you are driving with an impact: exceed it and the screw twists off rather than seating.

No. The DS835M is not Buy American compliant and is not ARRA compliant, and country of origin is listed as multiple. If your project carries a domestic-content requirement, this screw will not satisfy it.

Only in thin stock. A gimlet point Type A screw starts its own hole in light sheet metal, but it is not a self-drilling screw and has no drill flute. Into heavier gauge steel you need to pilot drill first, or switch to a self-drilling (Type TEK style) hex washer head screw. The #12 shank and 11 TPI coarse thread are built for thin sheet, wood and composition board.

Two options. The head is an indented hex measuring 0.305 to 0.312 in. across the flats, so a 5/16 in. hex driver or nut setter fits it, and the width across corners is 0.34 in. if you are checking socket clearance. The head is also slotted, with a slot width of 0.056 to 0.067 in. and depth of 0.077 to 0.093 in., so a flat blade works where you cannot get a driver socket in.

It is a #12 diameter screw with a 3 in. overall length. On a Type A sharp point screw of this length the thread runs nearly the full shank from the point up toward the head, so count on close to the full 3 in. for grip into the substrate once you deduct the thickness of the material you are fastening through.

Yes, the head has an integral washer face. The washer outside diameter is 0.398 to 0.432 in. and the washer thickness is 0.022 to 0.039 in., with head height of 0.139 to 0.155 in. That extra bearing surface spreads load on sheet metal and soft material so you do not need to add a separate flat washer.

Zinc plated carbon steel is the finish here, which is a dry-location and light-duty corrosion finish. It is fine for interior electrical work, panel and enclosure mounting, strut and framing attachment inside a building. For sustained exterior exposure, wet locations or treated lumber, specify a stainless or hot dip galvanized fastener instead.

These ship boxed in bulk, with an order minimum of 2500 pieces. That makes them a stocking item for an MRO crib or a contractor running repeat work, not a pick-a-handful item. Other sizes and quantities can be arranged by request.

It is a sheet metal style tapping screw, part of the Metallics JDS series, model DS835M. The thread is a spaced sheet metal thread to ASME B18.6.4, not a lag thread, and the head is a 5/16 in. indented hex with a slot rather than a heavy hex lag head. If you need real structural pull-out into framing lumber, order a lag screw instead.