Metallics JMHTB8701 Bolts M8 x 70 C10.9 Hx Tap Blt St-zn (Jar 100)

It's an M8 bolt with a 1.25 mm thread pitch, right hand, so it mates with a standard M8 x 1.25 coarse nut or tapped hole. Being a tap bolt, the threads run the full length of the 70 mm shank right up under the head, so there is no unthreaded grip section to work around when you are bolting through thin material or into a tapped hole of varying depth.

That is exactly what the JMHTB8701 is for. It's a grade 10.9 alloy steel bolt, heat treated, rated 150,800 psi minimum tensile and 136,300 psi minimum yield, with a hardness of Rockwell C32-39. In M8 x 70 it drops straight into any hole an 8.8 bolt of the same size and pitch occupied, but carries the higher clamp load the automotive and fleet trades call for. Going the other way (10.9 where 8.8 is specified) is fine on strength; going 8.8 where 10.9 is specified is not.

No. This bolt is not Buy American compliant and is not ARRA compliant, and country of origin is listed as multiple. If your contract carries a domestic sourcing clause, this part will not satisfy it and you need a fastener sourced and documented as US made.

The head is a standard hex with a washer face underneath, and the spec sheet gives a head width in the 12.73 to 13 range, which is the 13 mm across-flats head normally found on M8 bolts. A 13 mm socket or combination wrench is what you want in the pouch. The washer face under the head gives a clean bearing surface, so no flat washer is strictly required against a machined face.

The finish here is zinc over steel, which is a general purpose plating suited to indoor, sheltered, and light-duty outdoor exposure. It will handle a shop floor, a fleet bay, or enclosed equipment fine. For sustained weather, road salt, or wash-down exposure, specify a hot dip galvanized or stainless fastener instead; note that stainless will not give you 10.9 strength, so if the joint needs both, look at a coated alloy bolt.

They come in a jar of 100, and 100 count is the order minimum, so you buy the full jar rather than loose pieces. That is a practical shelf quantity for a service truck or an MRO crib where one size gets used repeatedly. Metallics lists other sizes and quantities in the MHTB and JMHTB series on request if M8 x 70 is not the length you need.

A tap bolt like the M8 x 70 JMHTB8701 is threaded the entire length of the shank, all the way to the underside of the head. A standard hex cap screw leaves a plain shank under the head. Use the tap bolt when you want maximum thread engagement into a tapped hole or when the grip length varies from joint to joint; use a partly threaded cap screw when you want the unthreaded shank taking shear in the joint line.

Be careful. The bolt itself is Rockwell C32-39 hardened alloy steel with a 136,300 psi minimum yield, so the fastener is far stronger than an aluminum thread. If you torque it to the values a 10.9 bolt can take, you will strip the housing long before the bolt yields. Either torque to what the parent material allows, or use a steel insert. The bolt's strength only pays off in a steel tapped hole or with a matching grade 10 nut.