System of Measurement


Product Type

Shoulder Diameter

Thread Size

Shoulder Length

Head Texture


AMPG has assembled the most complete line of nonferrous shoulder screws manufactured in North America.

Each shoulder bolt is made in one operation on state of the art Swiss Lathes. AMPG begins with precision ground DFARS compliant material. A finished part is made in one operation without the need for secondary broaching, slotting or thread rolling which can lead to many inconsistencies. AMPG’s process ensures shoulder diameter concentricity and tight tolerances. Each part is then carefully cleaned and packaged.

AMPG manufactures two types of precision shoulder screws, Knurled Head and Smooth Head. Both types have shoulders that are held to a precise diameter. This dimension determines the type of component the shoulder can accommodate.

Knurled head shoulder screws are made to ASME shoulder tolerance and have been the industry standard suitable for use in machinery and other critical mechanical applications. Smooth head, also known as precision-grade shoulder screws, have tighter shoulder tolerances making them ideal for use with ball bearings and other precision components.

Ordering Shoulder Screws: Shoulder screws are specified by shoulder diameter and shoulder length. For instance, a 5/16 x 3/8-inch shoulder screw has a shoulder diameter of 5/16-inch and shoulder length of 3/8 inch. This differs from other screws and bolts, where this size represents the screws thread size and a thread length.

Also known as stripper bolts, they’re commonly used as a stationary guide for stripper plates, as a pivot point for moving parts, and as a shaft for rolling parts. Shoulder screws have an unthreaded shoulder made with an undersized tolerance to fit most machinery and equipment.