Metallics JMHTB1250 Bolts M12 X 50 C8.8 Hx Tap Blt St-zn (Jar 50)

It is an M12 x 50 mm hex tap bolt. M12 refers to the nominal 12 mm shank diameter and 50 mm is the length under the head; standard M12 coarse thread is 1.75 mm pitch, so it mates with standard M12 coarse nuts and tapped holes.

A tap bolt is threaded the full length under the head, which is what separates it from a hex cap screw with a partial thread and plain shank. For the JMHTB1250 that means the whole 50 mm engages, so it works in a tapped hole of any depth up to 50 mm and gives full grip in thin stacked material such as strut, channel, and sheet steel brackets.

The JMHTB1250 is steel with a zinc plating, which is a mild corrosion coating meant for dry interior and protected service. For sustained outdoor exposure, wash-down areas, or coastal air, step up to hot dip galvanized or stainless. Also avoid pairing plain zinc plated steel directly against aluminum or stainless in wet conditions because of galvanic corrosion.

No. The JMHTB1250 jar contains bolts only, so order M12 hex nuts and flat or lock washers separately if you are bolting through rather than into a tapped hole. Match the nut to the bolt class, class 8 or higher, so the joint is not limited by the nut.

They ship 50 pieces in a jar. The jar pack is the usual format for an electrical contractor's van or a shop bin, so one order covers a run of strut clamps, hanger brackets, or equipment mounts without counting out loose hardware.

The Metallics part number is JMHTB1250, which breaks down as hex tap bolt, M12 diameter, 50 mm length, jar pack. Quote that number to get the zinc plated class 8.8 version rather than a stainless or galvanized equivalent.