Hobson UNF Hex Nut, 3/8"

There are 4 Hobson UNF hex nuts (UNF thread, Grade 5, high tensile steel, plain finish): 1/4" to 7/16". A hex nut is the standard six-sided nut. It is turned with a spanner or socket onto a bolt, stud or threaded rod of the same thread form, diameter and pitch.

Gr means the imperial grade-strength level of a screw or nut, for example Grade 2, Grade 5 or Grade 8. UNF means Unified National Fine Thread and TPI means threads per inch.

Where this product is used

• Machinery mounting and frame assembly using studs
• Locking up bolted flanges and brackets, with a washer under the nut
• Use in pairs on threaded rod or studs, tightened against each other, to help resist loosening
• Assemblies that will be painted, oiled or enclosed after fitting
• Medium-strength machinery and equipment work that needs more than Grade 2
• Choosing between the 4 items here: they cover diameters from 1/4" to 7/16"

Features

• 4 sizes: 1/4" to 7/16"
• UNF thread, hex nut
• Grade 5, High tensile steel, plain finish
• Pack quantity shown for each item
• Plain (uncoated) steel for dry indoor and machinery use
• Grade 5, medium-carbon quenched and tempered steel

Key specifications

Choosing the right option

Match the nut to the bolt, stud or rod: thread form, diameter and pitch must all agree. Sizes are nominal thread diameters in inches; compare the threads per inch with your bolt. Choose the class or grade to suit the bolt you are fastening, and confirm the pairing with your specification if the joint is load-critical.

Plain (uncoated) steel has no corrosion protection beyond a light oil film, and it rusts quickly once moisture reaches it. Keep plain parts for dry indoor use, machinery and assemblies that get painted, oiled or enclosed. Outdoors or in damp areas, a hot dip galvanised or 316 stainless alternative is the better choice.

In the SAE convention Grade 5 means medium-carbon, quenched and tempered steel. The thread is UNF (Unified National Fine). A finer pitch means more threads per inch and finer adjustment, and the nut or tapped hole must also be UNF. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related nuts: Hobson UNF Hex Nut, Grade 8, High Tensile Steel, Zinc, 1/2" and 5/8", Hobson UNF Hex Nut, Grade 5, Zinc Plated, 7/16", Pack of 50 and Hobson UNF Hex Nut, Grade 8, Plain, 1"-14, Box of 50.