Metallics RSB99 1/4-20 x 1/2 in. Round Head Combo Stove Bolt Screws with Hex Nut - Steel Zinc - Each

Hex nuts are included with the RSB99. Each 1/4-20 x 1/2 in. round head bolt ships with a machine screw hex nut sized for it, so you are not buying nuts on a separate line. Quantity is 100 per jar.

At 1/2 in. under the head there is only enough shank for thin stack-ups, roughly sheet steel to sheet steel plus the hex nut. If you are going through a 1/4 in. spacer, a strut nut, or doubled-up material, you will run out of thread. Add up your material thickness first and step up in length if it exceeds about 1/4 in. once you allow for nut engagement.

No. The RSB99 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your project has domestic sourcing requirements written into the specification, this part will not satisfy them.

Either one. The head is a combo drive, slotted and Phillips in the same head, so whatever is already in your pouch works. For the Phillips side use a #4 driver; the recess runs 0.255 to 0.268 in. diameter at 0.147 in. deep. The slot is 0.064 to 0.075 in. wide, which takes a standard cabinet-tip flat blade.

Steel with a zinc finish. That handles indoor and normally dry conditions, damp mechanical rooms and the like, but zinc plating is not a marine or sustained-wet coating. For exterior exposure, washdown areas, or coastal work, specify stainless instead.

Head and drive geometry conform to ANSI B18.6.3, the machine screw dimensional standard, and the steel is AISI 1006 to 1022 with a hardness of Rockwell B70 to B100. Minimum tensile strength is 60,000 psi. Those are the figures to put on a submittal sheet.

Yes. The thread is 1/4-20, 20 threads per inch, right hand, so both the bolt and the supplied hex nut interchange with any standard 1/4-20 UNC hardware on the job, including strut nuts and 1/4-20 tapped boxes. No left-hand or special pitch to watch for.

They come 100 to a pack, in a jar-style package intended to stay closed in a van bin rather than a loose bag. Handy if you are restocking a truck rather than pulling for one job.

It is stocked as an electrical-department fastener, and the intended field applications are electrical, plumbing, heating, and air conditioning work: hanging straps, box and enclosure assembly, bracket and channel connections where a through-bolt and nut is wanted instead of a self-tapper. The combo head means either an electrician or a mechanical tech can drive it with whatever bit is on hand.