Metallics MBHC33160 Bolts M33 x 160 C10.9 Hx Tap Blt St- (Box 20)

It's an M33 metric hex head cap screw 160mm long, made to DIN 931, which is the partially threaded hex bolt standard. So you get a plain shank under the head with threads at the business end, which is what you want when the bolt passes through a clearance hole and you need the unthreaded shank bearing in the joint.

The bolt is a Class 10.9 steel hex bolt with a minimum tensile strength of 120,350 psi and a minimum yield of 95,700 psi, hardness Rockwell C23-34. That is high tensile territory, well above a common commercial grade bolt, and it is the grade specified for heavy machinery mounting, strut and trapeze support, and similar loaded connections. Confirm the engineer's drawing calls for 10.9 or its equivalent before substituting.

Metallics lists the MBHC33160 as both Buy American compliant and ARRA compliant, with country of origin recorded as multiple. If your contract specification requires documentation of domestic origin on the specific lot shipped, ask for the mill paperwork with the order.

Nothing is bundled with the bolt, so the nuts and washers are a separate line on the order. You need M33 x 3.5 coarse thread nuts to match, and for a Class 10.9 bolt the nut should be grade 10 so the nut is not the weak point in the joint. Hardened washers under the head and nut are normal practice at this grade.

The finish is zinc over steel, which gives sacrificial corrosion protection suitable for indoor mechanical, electrical and plumbing work and sheltered exterior use. It is not stainless. For continuous wet exposure, coastal air, or chemical contact, specify a stainless fastener instead; zinc plating will eventually sacrifice itself and the steel underneath will rust.

The MBHC33160 is packaged as a box of 20, and the stated order minimum is 15 each. Other sizes and quantities can be had by request if 20 is not the count you need for the job.

Metallics puts this series in front of the electrical, plumbing, heating and air conditioning trades. In practice that means equipment and motor mounting, pipe and duct support, hanger and trapeze assemblies, and anywhere imported gear comes drilled for metric hardware rather than inch bolts.