Metallics JSRM90P 1/4-20 x 1-1/2 in. Round Head Phillips Machine Screws - 18-8 Stainless - Each

Use a #3 Phillips driver. The recess on the JSRM90P is 0.255 to 0.268 inch in diameter with a depth of 0.121 to 0.147 inch, so a #2 bit will sit shallow in it and cam out under torque. If you are running these with a drill, slow the speed down; stainless recesses gall easily.

Yes. The JSRM90P is a 1/4-20 machine screw, 20 threads per inch, which is the common coarse thread used with 1/4-20 strut channel nuts, spring nuts, and tapped equipment holes. At 1-1/2 inches long it gives you reach through a hanger, washer stack, or insulated standoff and still picks up full thread engagement. Machine screws like this need a tapped hole or a nut, they do not cut their own thread.

No. The JSRM90P is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, this is not the fastener to submit.

It will not sit flush. A round head stands proud of the surface by design: this one measures 0.16 to 0.175 inch in head height with a head width of 0.443 to 0.472 inch. That domed profile spreads load across the hole and is fine for cover plates, straps, and clamps, but if you need the head below the surface in a countersunk hole you want a flat head machine screw instead.

18-8 stainless is the usual choice for wet and outdoor general construction, and that is what these are made from. It holds up in rain, condensation, and washdown far better than plated carbon steel. Two cautions from the trade: 18-8 is not the grade for constant salt spray or chlorinated pool rooms (316 is), and stainless hardware in direct contact with aluminum or galvanized steel can set up galvanic corrosion, so isolate it where that matters.

The JSRM90P carries a minimum tensile strength of 80,000 psi and a hardness of Rockwell B85 to B95. Treat that as an approximation, since there is no single performance standard for stainless machine screws, and it is nowhere near a Grade 5 or Grade 8 carbon bolt. These are for electrical, plumbing, and HVAC mounting work, straps, plates, hangers, clamps, not for structural connections governed by a bolt spec on a drawing.

They come 100 to a jar, and the jar is the order minimum, so you are buying a full 100-count container rather than loose pieces. Shipping weight of the jar is listed at 2.03 lbs. The jar packaging is handy on a service van since the count stays contained in a bin.

No. The jar contains 100 round head Phillips machine screws only. Order 1/4-20 hex nuts, flat washers, or lock washers separately, or plan on landing them in a tapped hole or a 1/4-20 channel nut.

Order Metallics part JSRM90P, from the SRM series of round head Phillips machine screws. That number covers the 1/4-20 x 1-1/2 inch size in 18-8 stainless, 100 per jar. Other diameters, lengths, and quantities in the same series can be requested.