Hex Bolts & Cap Screws

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Expected delivery: Wed, Nov 18

Hex bolts and hex cap screws are the workhorse fasteners for machinery, structural brackets, truck bodies and equipment repair. This section covers inch sizes in UNC and UNF threads and metric sizes in class 8.8 and 10.9, with partial or full threads. Materials include Grade 2, Grade 5 and Grade 8 steel plus 18-8 and 316 stainless, in plain, zinc, yellow zinc and hot-dip galvanized finishes.

What to check before you order

  • Grade or property class. Match the grade to the load. Grade 5 covers most equipment work, and Grade 8 is for high-stress joints such as suspension and heavy machinery. The hex bolt grades guide shows head markings.
  • Thread pitch. A 1/2" bolt comes in 1/2"-13 coarse and 1/2"-20 fine. They will not interchange, so confirm the nut or tapped hole first.
  • Length and thread length. Measure from under the head. Longer bolts are often partially threaded, which leaves a smooth shank in the shear plane.
  • Finish. Hot-dip galvanized bolts need galvanized nuts, because the coating adds thickness to the threads.

Common questions

Is a Grade 8 bolt always the safer choice?

Not always. Grade 8 is stronger but less ductile than Grade 5. Use the grade the equipment maker or engineer specifies.

Pair your bolts with matching nuts and washers, or browse all fasteners.

Hex Bolts & Cap Screws: page 27

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