Machine Screw 4-40 x 1/4 inch p-ph-s 237-5909-00

Machine screw with 4-40 thread and 1/4 inch long with phillips pan head and SEMS integrated external tooth lockwasher.

(SEMS is a fastener industry term that refers to a screw or bolt which has a captive washer.)

Reference:

4004-01003-04237-5909-00

Fastener part numbering system explained:

The last 2 digits (XX) of the 4 digit fastener part number prefix (40XX-12345-12) indicates the standard stud size of the bolt or screw. For example, part No.4006-01030-12 indicates a No.6 stud diameter (.138") fastener.

The 2 digit part number suffix for bolts and screws (-12, -04, -16, etc) indicates the number of 1/16" length increments of the fastener. For example, part No.4004-01003-04 indicates a screw that is 4/16" long or 1/4" long.

The middle 5 digits describe the fastener head style or other features.

Basic diameters and threads of Standard SAE (Society of American Engineers) numeric system small machine screws are shown below.

The diameters of machine screws are indicated with the number of threads per inch. Here is a list of common sizes in inches:

2-56: 0.0860" or 43/500" in diameter; 56 threads per inch
4-40: 0.1120" or 14/125" in diameter; 40 threads per inch
5-40: 0.1250" or 1/8" in diameter; 40 threads per inch
6-32: 0.1380" or 69/500" in diameter; 32 threads per inch
8-32: 0.1640" or 41/250" in diameter; 32 threads per inch
10-32: 0.1900" or 19/100" in diameter; 32 threads per inch
10-24: 0.1900" or 19/100" in diameter; 24 threads per inch
12-24: 0.2160" or 27/125" in diameter; 24 threads per inch