These Variable Screw Thread Measurement Systems have several more specific designations: Tri-roll Gage; Bi-Point Gauge; Segment Gage.

Tri-Roll Gauge is usually used for external screw threads. Using a Tri-Roll Gage for internal screw threads is only an option for larger diameter screw threads. It is valuable because the three points of contact are self-positioning on the thread, which makes it an easy test to make. The Rolls of a Tri-Roll Gauge have different functions and forms depending on its function.

Bi-Point Gage is often used on internal screw threads. There are a couple of brands which also use the Bi-Point system on external screw threads. When used on internal screw threads the Bi-Point Gauge is self-positioning. When used on external screw threads the gage measurement must be noted on the hi-point, the largest diameter, which may take a little more skill than if it were self-positioning.

Variable Screw Thread Measurement Systems are ideal in a couple of situations.

1. High volume gauging applications.
2. In cases where GO/NOGO gages are wearing too rapidly.
3. For use on gummy materials, like stainless steel and aluminum.
4. When demanded by your customer.
5. In System 22 or System 23 applications.
6. When SPC of the screw thread is desired.
7. For odd-ball screw thread forms or configurations where GO/NOGO gages are not feasible.

Gage Crib Worldwide Inc. specializes in screw thread measurement tools and can work with you to determine the best gauging system for your specific application. If you desire an alternative method of measuring your threads, like these Variable Screw Thread Measurement Systems; contact us and we can guide you to the correct screw thread system to meet your quality assurance requirements.