Hobson UNC Hex Bolt, 5/8" / 5 1/2"

The Hobson UNC hex bolt range has 105 items in grade 8, plain finish: sizes 1/4" to 2", with lengths from 3/4" to 15". 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

• Bolting steel plate, angle and flat bar together through drilled clearance holes, with a nut and washer on the far side
• Fixing machinery feet, guards and mounting brackets where the bolt may need to come out again for servicing
• Securing timber to steel brackets or flitch plates, with a flat washer under the head to protect the timber
• Dry indoor machinery, tooling and equipment
• Heavy-duty assemblies and machine building where a high-strength fastener is wanted
• Choosing between the 106 items here: they cover diameters from 1/4" to 2" and lengths from 3/4" to 15"

Features

• 15 sizes: 1/4" to 2"
• Grade 8, Plain finish
• Lengths from 3/4" to 15"
• 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
• Grade 8 alloy steel for heavy-duty work

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 a bolt and nut set: see Hobson UNC Hex Bolt and Nut, Grade 8, Plain, 5/16" to 1-1/2" x 3/4" to 10".

A plain finish means bare steel with only a light oil film on it. It will rust quickly in damp conditions. It suits dry indoor jobs, machinery, and assemblies that will be painted, oiled or enclosed. Where the job is outside or damp, move to hot dip galvanised or 316 stainless.

The thread is UNC (Unified National Coarse), the general-purpose inch thread. Use it with UNC nuts and tapped holes only. 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 B, Hobson UNC Hex Bolt and Nut, Grade 8, Plain, 5/16" to 1-1/2" x 3/4" to 10" and Hobson UNC Hex Bolt, Grade 5, Plain, 1/4" to 7/16" x 3/4" to 6".