Taper Gages

Taper Gages

Thread Taper is the change in pitch diameter over the length of a connection, typically designated in inches per foot. For all API related connections, measuring thread taper is not only an industry wide practice; it is an mandated inspection.

During the manufacturing process in any industry, taper must be accurately measured and quantified to avoid mismatched tapers. When subjected to a service load, taper error on threaded connections can lead to galling, improper fit, improper thread engagement, and reduced performance.

For the most accurate taper inspection, use Gagemaker taper gages to verify both the threaded pin and coupling meet all customer and industry requirements. Our taper gages are the best choice for measuring and controlling taper values. When connections are properly manufactured utilizing Gagemakers JSS™ precision taper gages, product performance is maximized.

Taper ET 76000 on Part 300x217 - Taper Gages

External Taper

Gagemaker’s external taper gages inspect variation in connection taper. External taper gages are shipped with .072″ diameter contact points as standard. Select the proper contact point for your particular connection. All indicators are .001″ resolution, but higher resolution indicators are available for some models.


Taper IT 6000 on Part 300x263 - Taper Gages

Internal Taper

Gagemaker’s internal taper gages measure variation in connection taper. Taper gages are shipped with our standard set of .072″ diameter contact points (T072), unless specified otherwise. IT-6001 includes one set of extension rods up to 13 3/8″. Higher resolution indicators are available.


Extensions have #10-40 threads.