What is a Precision Shoulder Screw?
Resembling a Socket head cap screw, Precision Shoulder Screws have an enlarged, unthreaded cylindrical shoulder under the head, and are used to hold parts together within a precision assembly. Technically classified as Electronic Hardware, Precision Shoulder Screws are not governed by any official IFI, ANSI or ASME standard.
What materials and sizes are available?
Common sizes are readily available off the shelf in type 18-8/303 and 416 Stainless Steel. Standard Shoulder Diameter sizes are 1/8 to 1/2 Inch and M4 to M12 Metric. The thread class is 2A, vs. Stripper / Shoulder Bolts , which have 3A thread.
What information do I need for ordering?
The easiest way to order is by manufacturer part number (MSB and PZM are common prefixes). If you don’t have one, you’ll need to specify shoulder diameter, shoulder length, thread size, material and drive type.
Yes! One surefire way to save money and shorten delivery time is to cross the OEM brand part on your bill of materials to a functional equivalent. Popular brands include: Amatom, Cambion, Concord, Globe, HH Smith, Keystone, Lyn-tron, Misumi, Pic Design, RAF, and WM Berg. A comprehensive selection of Precision Shoulder Screws is also offered by McMaster-Carr (tight tolerance series), MSC, and Grainger. You can also find Precision Shoulder Screws under their Mil-Spec numbers, which include MS51575 and MS51576 and are available DFARS compliant with full paperwork.
What level of certification is required?
Generally, a Certificate of Conformance or a COC is sufficient for your customer. Full certifications with material certs and test reports are often available for USA-made and Mil-Spec parts for a fee.