Metallics JSRM32P 1/4-20 x 1 in. Round Head Phillips Machine Screws - 18-8 Stainless - Each

The JSRM32P is a 1/4-20 machine screw, 1 inch long, so it threads into any standard 1/4-20 tapped hole or nut at 20 threads per inch. Machine screw threads are uniform, so the 1 inch length is the only thing you need to match to your stack-up: grip plus whatever engagement you want in the tapped member.

The round head measures 0.443 to 0.472 inch across and stands 0.16 to 0.175 inch above the surface. It is a non-countersunk head, so it bears on top of the material rather than sinking in. If your hole is a countersink or your cover has to sit flush, you want a flat head instead of this round head version.

No. The JSRM32P is listed as not Buy American compliant and not ARRA compliant, with country of origin shown as multiple. For a job with domestic-sourcing requirements you need a fastener carrying a domestic origin statement.

Use a #3 Phillips. The recess on the JSRM32P runs 0.255 to 0.268 inch in diameter with a depth of 0.121 to 0.147 inch, which is bigger than a #2 bit will properly seat in. Driving these with a #2 is how you cam out and chew the recess, especially in stainless.

They are 18-8 stainless, which is the austenitic grade used for general corrosion resistance in wet and outdoor work, so yes for exterior enclosures, condensate pans, and rooftop mechanical mounting. Hardness is Rockwell B85-B95. 18-8 is not the grade for direct marine salt immersion, where 316 is the usual step up.

They ship in a jar of 100, and 100 is the order minimum. Figure roughly 1.62 lbs for the jar. Metallics lists other sizes and quantities of the SRM round head machine screws by request.

80,000 psi minimum, to SAE material standard. Metallics is explicit that tensile values for stainless machine screws are approximations, since there is no single performance standard for stainless machine screws. If a drawing calls out a specific graded strength class, a stainless machine screw is the wrong fastener for that callout.

Metallics lists the SRM round head machine screws for the electrical, plumbing, heating and air conditioning trades: fastening into tapped holes in enclosures, strut fittings, panel hardware, equipment brackets, and duct and unit mounting. A machine screw needs a tapped hole or a nut on the back side, so it is not a self-tapping or sheet metal screw.