Pipe threads are manufactured in many forms, but the most common types are straight and tapered threads. Straight pipe threads are gaged with the “GO” & “NO GO” process like regular threads, but tapered pipe threads require an entirely different gaging method: A series of L checks.

                The 3 main types of L checks are the L-1, L-2 (for external threads) or L-3 (for internal threads) & the 6-Step Check. To learn about these checks in detail, visit our post detailing the Hand Gaging of NPT Threads: Hand Gaging of NPT Threads. In this video, we will be focusing on the L-1 check, as it is the most common check used in powered pipe thread verification.