Hobson SHSOZC0250100 1/4" x 1" UNC Socket Head Cap Screw, Alloy Steel, Zinc

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 (manufacturer-stated).

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. The table gives the threads per inch from the Hobson thread table, for the sizes it lists (manufacturer-stated).

Pack quantity is shown for each item in the table. It changes with the size and length.

The published product details do not give the socket (key) size, head dimensions or thread length for these screws, so none are published. Check the key size against a screw in hand.

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
• There are 15 items with diameters from 1/4" to 5/8" and lengths from 3/4" to 3", so work out the size you need first and then read across the table.

Choosing the finish

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.

Thread and strength

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.

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

Common specifications

Key specifications

Selecting the right option

Choose the thread form first: the screw must match its nut or tapped hole in thread form, diameter and pitch. Sizes are nominal diameters in inches; compare the threads per inch in the table with your thread. By convention the length of a socket head cap or button head screw is measured from under the head; the published product details do not state the measuring point. Check the key size against the screw in hand, as the published product details do not state it.

Related products

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".