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

The Hobson UNC socket head cap screw has a UNC (Unified National Coarse) thread and is alloy steel, zinc finish. There are 15 items: 1/4" to 5/8", in lengths from 3/4" to 3". Head style: SHCS, Socket Head Cap Screw.

The head carries a socket, so the screw is driven with a key or bit instead of a spanner. UNC means Unified National Coarse Thread and TPI means threads per inch. It changes with the size and length.

Where this product is used

• Machine building and tooling, where a high-strength cap screw sits recessed in a counterbored hole
• Clamping plates, covers and housings down onto tapped holes
• Motor, pump and gearbox mounting where the head is recessed below the surface
• Dry, indoor and sheltered locations such as workshops, enclosed machinery and interior fit-out

Features

• 15 items: 1/4" to 5/8"
• UNC thread, socket head cap screw
• Alloy steel
• Zinc finish
• Pack quantity shown for each item
• Zinc plated finish, for indoor and sheltered locations
• Made from alloy steel

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.

These socket head cap screws are zinc plated, which means a thin electroplated layer of zinc over the steel. That is enough for dry, indoor or sheltered use; it is generally not recommended for external applications and is not suitable for treated pine. For weather-exposed work, look at a hot dip galvanised version instead; within about 1 km of the sea, 316 stainless is generally the safer choice.

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 UNC Socket Head Cap Screw, Alloy Steel, Plain, #4-40 to 1-1/2", Hobson UNF Socket Head Cap Screw, Alloy Steel, Plain, #10-32 to 1" and Hobson UNC Button Head Socket Screw, Alloy Steel, Plain, #10-24 to 1/2".