How do you measure a shoulder screw?

Size is the shoulder diameter and length is the length of the shoulder—measure length from under the head to the end of the shoulder. An additional dimension is thread size, which is always smaller in diameter than the shoulder, and ranges from 10-24 to 5/8-11 for the common sizes.

What is a precision shoulder screw?

Precision Shoulder Screws, also known as shoulder bolts, are fasteners with an unthreaded cylindrical section, or shoulder, between threads and screwhead. The shoulder is larger in diameter than the threaded section and provides an axis around which close-fitting moving parts operate.

How do you spec a shoulder bolt?

Q: How to measure a shoulder bolt Thread size is one standard size smaller than the shoulder diameter and doesn’t need to be specified, except for: A bolt with a 1/2″ diameter shoulder has a 3/8″-16 thread. A 5/8″ diameter shoulder has a 1/2″-13 thread.

What grade is a shoulder bolt?

The major thread diameter of a shoulder screw must not exceed the shoulder diameter. Commercial-grade shoulder screws have UNC class 3A threads. So, a commercial-grade screw with a ¼-in. -diameter shoulder has #10-24 threads.

What is a shoulder screw?

Shoulder screws, or shoulder bolts, are machine screws that have an unthreaded shoulder under the head that is larger in diameter than the threads. It is this enlarged shoulder that determines the nominal size of the screw.

What size is a 10mm bolt?

Metric Shoulder Bolt Dimensions

Shoulder Diameter (A) Thread (C) Head Diameter (E)
8mm 6mm x 1.0 13mm
10mm 8mm x 1.25 16mm
12mm 10mm x 1.5 18mm
16mm 12mm x 1.75 24mm

What are precision screws?

Precision Fasteners provides thread cutting, plasform, Hi-Form® and other types of thread forming screws. Manufactured screws are made with all standard drives as well as specialty drives including Quadrex, Six Lobe and Square / Phillips / Slot combinations.

Why do Bolts have shoulders?

Bolt Shoulders exist for two reasons. The first is to create an area on the bolt where sheering is less likely to occur. If a load is pulling sideways against the unthreaded area of a bolt then the bolt will be less likely to snap as the areawhere the pressure is being placed is stronger than the threaded portion.

Are shoulder bolts stronger than regular bolts?

The thread neck is the weakest point of a shoulder bolt because it has the smallest diameter. This is why the torque values for shoulder bolts are about 40% less than the torque values for standard bolts with the same thread size and pitch, as shown in Table 1.

Why do bolts have shoulders?

Do shoulder bolts need washers?

They do not generally have a pointed tip, which means that predrilling is necessary. Mated nuts will also need to be used and often washers are a good idea as well, depending on how much pressure the fasteners will be under. Sometimes called shoulder bolts, these fasteners are also available in square shapes.