Hobson UNC Hex Bolt and Nut, 5/8" / 3 1/2"

The Hobson UNC hex bolt and nut range has 114 items in grade 8, plain finish: sizes 5/16" to 1-1/2", with lengths from 3/4" to 10". Grade 8 is high tensile, and corresponds to metric class 10.9. UNC means Unified National Coarse Thread and TPI means threads per inch.

Where this product is used

• Fabrication, repair and maintenance jobs where the joint is tightened from both sides with spanners
• Machinery guards, frames and conveyor supports that are bolted rather than welded
• Workshop and site kits where the nut should arrive with the bolt instead of being ordered separately
• Workshop jobs where the part is protected by its surroundings
• Heavy-duty assemblies and machine building where a high-strength fastener is wanted

Features

• 10 sizes: 5/16" to 1-1/2"
• Grade 8, Plain finish
• Lengths from 3/4" to 10"
• Pack quantity and part number for every item
• Proof load and minimum tensile strength
• Spanner size (A/F) by size
• Plain finish: suited to dry indoor, oiled, painted or enclosed use
• Heavy-duty Grade 8 alloy steel

Key specifications

Choosing the right option

Choose the thread form first: the nut must match the bolt in thread form, diameter and pitch. Length is measured from under the head to the end of the bolt. For the bolt on its own: see Hobson UNC Hex Bolt, Grade 8, Plain, 1/4" to 2" x 3/4" to 15", List A.

Plain steel carries no protective coating apart from a light oil film, which is why it rusts quickly if it gets wet. That makes it a good fit for dry indoor work, machinery, and assemblies that are painted, oiled or enclosed after fitting. For anything outdoors or damp, choose a hot dip galvanised or 316 stainless option instead.

UNC is the coarse inch thread, the general-purpose choice; it only mates with UNC nuts and tapped holes of the same diameter. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related hex bolts: Hobson UNC Hex Bolt, Grade 8, Plain, 1/4" to 2" x 3/4" to 15", List A, Hobson UNC Hex Bolt, Grade 8, Plain, 1/4" to 2" x 3/4" to 15", List B and Hobson UNC Hex Bolt and Nut, Grade 5, Plain, 1/4" to 7/16" x 3/4" to 6".