Metallics JDS177SS 14 x 1-1/4 in. 3/8 Indented Hex Head Slotted Sharp Point Tapping Screws - 18-8 Stainless - Each

The JDS177SS takes a 3/8 inch hex driver or socket. Head width across flats runs 0.367 to 0.375 in. and across corners measures 0.409 in., so a standard 3/8 nut driver seats correctly. It also has a slot across the head (0.064 to 0.075 in. wide, 0.083 to 0.101 in. deep), so a medium flat blade screwdriver works when you cannot get a socket in.

It will self-thread into sheet metal. The JDS177SS is a Type A tapping screw with a gimlet (sharp) point, which is the point style meant to pierce and form its own thread in thin sheet steel, aluminum sheet and similar light gauge material. Thread pitch is 10 threads per inch to the ASME B18.6.4 thread standard. For heavier stock or structural material you still want a pilot hole, and a Type A screw is not the right choice for thick plate.

You can, but understand the corrosion risk. Metallics states that fastening stainless steel parts to aluminum or steel can create a galvanic couple in some environments, which attacks the less noble metal (the aluminum or the carbon steel, not the screw). Outdoors, in coastal air or anywhere wet, that matters. In dry interior work it is normally a non-issue. If you are anchoring aluminum in a wet or exterior location, isolate the joint or use a matched-metal fastener instead.

These ship as a jar, and the order minimum is 100 pieces. The 18-8 stainless indented hex head slotted tapping screws come packaged in a jar rather than loose counts, so plan the job around hundred-piece increments.

Yes, the head is an indented hex with an integral washer face. Washer outside diameter runs 0.480 to 0.520 in. and washer thickness 0.030 to 0.050 in., with overall head height 0.172 to 0.190 in. That bearing surface spreads load on thin sheet and strap, so you usually do not need a separate washer under the head.

No. The JDS177SS is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If the project carries a domestic sourcing clause, these will not clear it and you need a domestically sourced fastener instead.

Case hardness on the JDS177SS is Rockwell C28-38, which is what lets a Type A tapping screw form threads in sheet metal without stripping the drive. The slotted hex head is the weak link in high torque work, so drive it with a 3/8 socket rather than leaning on a flat blade if you are setting a lot of them.

Metallics lists these for the electrical, plumbing, heating and air conditioning industries. Typical use is hanging and fastening in sheet metal: duct and plenum work, strut and strap, device boxes, enclosures, and fixture mounting where the 18-8 stainless is wanted for damp or corrosive locations. The 1-1/4 in. length suits light assemblies rather than deep stack ups.

Head dimensions follow ASME B18.6.3-2010 and the threads follow ASME B18.6.4. That matters on spec driven work where a submittal has to name a standard, and it means the 3/8 head and 10 TPI thread will match other B18.6 conforming hardware on the same assembly.