Threads

Machine Screw Diameters
By H. J. Coventry

The Miniature Locomotive, July-August 1954

Machine screws are numbered as distinct from Cap Screws, Bolts, etc, and range usually from #0 to #12. A convenient method of finding the exact diameter if a table is not handy is as follows:


 * Multiply the number of 13 and add sixty thousandths. The answer will be thousandths.

Examples:


 * #0 -- 0 multiplied by 13 equals 0, plus 0.060 equals 0.060
 * #3 -- 3 multiplied by 13 equals 39, plus 0.060 equals 0.099
 * #5 -- 5 multiplied by 13 equals 65, plus 0.060 equals 0.125
 * #10 -- 10 multiplied by 13 equals 0.130, plus 0.060 equals 0.190