Metallics JMHTB420 Bolts M4 X 20 C8.8 Hx Tap Blt St-zn (Jar 100)

It's an M4 bolt 20mm long with a 0.7mm thread pitch, right hand thread. That's the standard coarse metric pitch for M4, so it mates with M4 nuts and M4 tapped holes. Because it's a tap bolt, the thread runs the full length of the shank right up under the head, so there is no unthreaded grip section to worry about with thin brackets or shallow tapped holes.

Yes, and that's the job the JMHTB420 is made for. Property Class 8.8 means medium carbon steel, heat treated, with 120,350 psi minimum tensile and 95,700 psi minimum yield, measured at Rockwell C23-34 hardness. It's the metric equivalent tier to an SAE Grade 5 bolt, which is the normal choice for motor mounts, equipment feet and bracketry. For structural anchorage into concrete you want an anchor, not a tap bolt.

These are zinc plated carbon steel. Zinc handles indoor mechanical rooms, equipment rooms and general HVAC work fine, and gives moderate protection in sheltered outdoor use. For continuous wet exposure, coastal air, or anything washed down regularly, specify stainless instead; plated zinc will eventually bloom white and then rust through.

The JMHTB420 ships as a jar of 100 bolts, and the jar is the minimum order unit. One jar weighs 249 g. If you need a different count or a different M4 length, Metallics offers other sizes and quantities in the MHTB and JMHTB tap bolt series on request.

A tap bolt is threaded the entire length of the shank, right up under the hex head, instead of having a plain shoulder below the head. That matters when you're threading into a tapped hole of unknown depth or clamping thin material, because you get usable thread wherever the joint lands. A partially threaded hex cap screw is the better pick when you want the smooth shank bearing in a shear joint through aligned holes. The JMHTB420 also carries a washer face under the head, which gives a cleaner bearing surface on the part you're clamping.

No. These are not Buy American compliant and not ARRA compliant, and the country of origin is listed as multiple. If your project has a domestic-content requirement on fasteners, you'll need a domestically sourced bolt instead.

Metallics lists the JMHTB420 for electrical, plumbing, heating and air conditioning work, and it's a common consumable in automotive and truck repair. Typical uses are mounting a motor to machinery, securing small brackets, panels and equipment feet, anywhere an M4 tapped hole or nut is involved. MRO stockrooms keep a jar on the shelf for exactly that kind of small-fastener call.