Socket Products

Choose the head profile

• Socket head cap screws: tall cylindrical head, made to sit in a counterbored hole. Inch #0 to 2-1/2" in alloy steel (ASTM A574); metric M1.6 to M48 in Class 12.9 (ISO 4762 / DIN 912).
• Button head cap screws: low, rounded head for a finished look. Inch #0 to 3/4", metric M2 to M24.
• Flat head cap screws: countersunk head that sits flush with the surface. Inch #0 to 1-1/2", metric M2 to M24.
• Low head cap screws: shorter head for tight clearance. Metric versions follow DIN 7984.
• Set screws: no head. They lock a collar, pulley, gear or knob onto a shaft.
• Shoulder screws: an unthreaded shoulder with a smaller thread, used as a pivot or guide. Inch shoulders 1/8" to 1-1/4", metric 6 mm to 24 mm.

Material and strength class

Inch alloy steel socket head cap screws are made to ASTM A574. Button and flat head alloy cap screws follow ASTM F835, and alloy steel set screws follow ASTM F912. None of these carry an SAE grade, so don't call them Grade 8. Metric alloy steel is listed by property class: 12.9, 10.9 or 8.8. Inch stainless is 18-8 or 316. Metric stainless is A2 or A4. Set screws also come with nylon or brass tips.

A flat (countersunk) head is not as strong as a socket head of the same size. Don't swap one for the other where the drawing calls for a socket head cap screw.

Shop by material: alloy steel, Class 12.9, 18-8 stainless and 316 stainless.

Set screw points

Cup point is the most common. Also stocked: flat, cone, oval and dog point, knurled cup, and nylon-pellet versions. Set screws carry a compressive load, not tension.

Thread callouts

Inch sizes read diameter-threads per inch x length: #10-32 x 1/2" is fine thread (UNF), 1/4"-20 x 1" is coarse (UNC). Metric reads diameter-pitch x length: M6-1.0 x 20 mm. Shoulder screws list shoulder diameter x shoulder length, then the thread, for example 1/2" x 1" with a 3/8"-16 thread.

Finish

Alloy steel comes in thermal black oxide, black oxide, plain, or zinc (including zinc bake and mechanical zinc). Black oxide is a dark conversion finish with minimal corrosion resistance. It's best kept indoors and dry, and oil helps. Zinc bake is the supplier's process name. Stainless is passivated. Some cap screws have a pre-applied nylon patch or pellet for thread locking.

Drive and length

Most socket products take a hex key (Allen key); square head and slotted set screws are also listed. Find the key size for each screw in the wrench and Allen key size chart. Socket head and button head lengths are measured from under the head. Flat head length is overall. Set screw length is overall. Shoulder screws are measured by shoulder length.

Packages and bulk boxes

Most socket products come as a Package or a Bulk Box, for example 100 / 1,000 or 100 / 5,000 on small sizes. Each variant shows its count. Need volume pricing? See wholesale.