Hobson UNF Button Head Socket Screw, 1/4"

The Hobson UNF button head socket screw has a UNF (Unified National Fine) thread and is alloy steel, plain finish. There are 2 items: 1/4" and 5/16", in lengths from 3/4" to 1". Head style: BHCS, Button Head Cap Screw.

The head is low and domed, with a socket drive. UNF means Unified National Fine Thread and TPI means threads per inch. All items are supplied as a box of 100.

Where this product is used

• Low-profile fixing where a smooth rounded head is wanted, such as guards, covers and panels
• Machine guards and enclosures where a rounded head will not snag clothing or hands
• Control panels and cabinet covers that are removed for access
• Workshop jobs where the part is protected by its surroundings

Features

• 2 items: 1/4" and 5/16"
• UNF thread, button head socket screw
• Alloy steel
• Plain finish
• Pack quantity shown for each item
• Uncoated plain steel: paint, oil or enclose it for protection
• 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. 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. Plain finish is normal for high-strength alloy socket screws in tooling and machine building.

UNF is the fine inch thread: the finer pitch gives more threads per inch and a finer adjustment. It only mates with UNF 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 socket screws: Hobson UNC Button Head Socket Screw, Alloy Steel, Plain, #10-24 to 1/2", Hobson UNC Button Head Socket Screw, Alloy Steel, Zinc, 1/4" to 3/8" and Hobson UNC Socket Head Cap Screw, Alloy Steel, Plain, #4-40 to 1-1/2".