Hobson UNC Hex Bolt and Nut, 3/8" / 6"

The Hobson UNC hex bolt and nut range has 40 items in grade 5, plain finish: sizes 1/4" to 7/16", with lengths from 3/4" to 6". Grade 5 is high tensile, and corresponds to metric class 8.8. 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
• Replacing a bolt and nut pair of the same thread form and diameter
• 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
• Medium-strength machinery and equipment work that needs more than Grade 2
• The 40 items cover diameters from 1/4" to 7/16" and lengths from 3/4" to 6", confirm the size against your drawing before ordering

Features

• 4 sizes: 1/4" to 7/16"
• Grade 5, Plain finish
• Lengths from 3/4" to 6"
• Pack quantity and part number for every item
• Proof load and minimum tensile strength
• Spanner size (A/F) by size
• Uncoated plain steel: paint, oil or enclose it for protection
• Grade 5 medium-carbon steel, quenched and tempered

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 5, Plain, 1/4" to 7/16" x 3/4" to 6".

These hex bolt and nut sets are plain steel, with no coating beyond a light oil film, so they rust quickly in moisture. 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.

In the SAE J429 convention Grade 5 is medium-carbon, quenched and tempered steel, shown by three radial lines on the head. 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 5, Plain, 1/4" to 7/16" x 3/4" to 6", Hobson UNC Hex Bolt and Nut, Grade 5, Plain, 1/4" x 3", Pack of 150 and Hobson UNC Hex Bolt and Nut, Grade 8, Plain, 5/16" to 1-1/2" x 3/4" to 10".