Hobson UNC Socket Head Shoulder Screw, 1/4" / 1"

The Hobson UNC socket head shoulder screw has a UNC (Unified National Coarse) thread and is alloy steel, plain finish. There are 13 items: #10-24 to 1/2", in lengths from 3/8" to 2-1/2". A shoulder screw has an unthreaded shoulder under the head, then a smaller threaded section.

Shoulder length is the length of the shoulder, not the length of the thread. UNC means Unified National Coarse Thread and TPI means threads per inch. All items are supplied as a box of 25.

Where this product is used

• Guides and sliding parts that need a precise diameter to run on
• Bearing shafts and small axles, where the shoulder gives a true diameter for the bearing
• Replacing shoulder screws where both the shoulder length and the thread size have to match
• Assemblies that will be painted, oiled or enclosed after fitting
• The 13 items cover diameters from 1/4" to 1/2" and lengths from 3/8" to 2-1/2", confirm the size against your drawing before ordering

Features

• 13 items: #10-24 to 1/2"
• UNC thread, socket head shoulder screw
• Alloy steel
• Plain finish
• Pack quantity shown for each item
• Plain finish: suited to dry indoor, oiled, painted or enclosed use
• Alloy steel construction

Key specifications

Choosing the right option

Choose the thread form first: the screw must match its nut or tapped hole in thread form, diameter and pitch.

Plain steel carries no protective coating apart from a light oil film, which is why it rusts quickly if it gets wet. 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 tooling and machine building, plain alloy socket screws are the usual choice, where the assemblies are usually oiled or enclosed.

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 socket screws: Hobson Metric Socket Head Shoulder Screw, Grade 12.9 Alloy Steel, Plain, M5 to M20 and Hobson BSW Socket Head Shoulder Screw, Plain, 3/8 x 1/2 x 1, Box of 25.