Metallics JSRM40 1/2-13 x 1 in. Round Head Slotted Machine Screws - 18-8 Stainless - Each

The JSRM40 is a 1/2-13 machine screw, 1 inch long. That's a 1/2 inch nominal diameter with 13 threads per inch, which is the standard UNC coarse pitch for 1/2 inch. It will thread into any 1/2-13 tapped hole or nut; a 1/2-20 fine thread nut will not accept it.

They're 18-8 stainless, the common austenitic grade used where plain steel would rust, so they hold up in damp interior and general outdoor service. For salt spray or coastal exposure, 316 is the grade normally specified instead.

Tensile strength is rated 80,000 psi minimum with a hardness of Rockwell B85-B95. Keep in mind the manufacturer states tensile values for stainless screws are approximations, since there is no single performance standard for stainless machine screws. For a structural connection with a defined strength class, use a graded steel bolt rather than 18-8 stainless.

Slotted drive, so a flat blade screwdriver. The head is a round head, which sits proud of the surface with a domed profile rather than countersinking. If you need the fastener flush with the material, you want a flat head screw in a countersunk hole instead.

They ship in a jar with a 50 count minimum order, so the smallest quantity is 50 pieces. Metallics notes other sizes and quantities are available by request.

The JSRM40 is flagged ARRA compliant and Buy American compliant in the manufacturer's data, with country of origin listed as China. On a federally funded project, check which standard your specification cites, since the two designations carry different sourcing tests.

The jar comes in at 3.73 lbs, in a container measuring 3.5 x 3.5 x 5.75 inches, so it drops into a standard parts bin or van shelf without repacking.