Tapping screw

Below is a list of common tapping screw user’s complaints to screw suppliers:
 1. The screws strip out.
2. The screws will not seat in the application.
3. The screw break during installation.
4. The screw cause excessive driver bit usage.

Many times a thorough review of the screws reveals that they conform to all of their applicable requirements. The only logical conclusion to reach then is that the user is somehow unintentionally using the tapping screws inappropriately. After the screw supplier determines his screws are not the root cause of the user’s assembly problem he must work with the user to help determine what the root cause of the problem is. One of the most common assembly mistakes made by tapping screw users is inappropriate hole size selection. Extensive tapping screw hole size guidance is given in Appendix B of the American Society of American Engineers standard for tapping screws, ASME B18.6.4. This document contains recommended hole sizes for the use of all of the standard types of inch tapping screws from #2 through 3/8 inch in a variety of materials having a range of thicknesses from 0.018 through 0.500 inches. I will not reproduce the entire Appendix B in this article but I will provide excerpts to illustrate what information it does contain: