For buttress connections to be compliant under the 16th edition of the API 5B, thread run-out inspection is required.

When inspecting buttress run-out with a Gagemaker BR-2001, inspectors often question where to place the contact point on the thread. Now, the new API 5B Section 5.3.3.4 specifies the location of the inspection point.

When the thread path terminates/vanishes after the triangle make-up stamp, place the contact point at the apex of the triangle.

When the thread path terminates before or within the triangle make-up stamp, place the contact at the thread’s termination point.

Thread runout is the measurement of the abruptness with which the buttress thread is terminated at the triangle end of the thread. A rapid pull-out of the cutting tool results in steep slope at the end of the thread. This causes high stress at the contact point when the coupling is made-up.

Buttress runout gages ensure proper thread pullout on runout type threads. Gagemaker buttress runout gages (BR-2000 Series) have standard 1″ and 2″ point spacing. Includes one contact point (TBR) and shoes.

Gage includes two shoes and one TBR contact point.