Taperlock thread plug gauges are used to check the accuracy and dimension of parts that require high tolerances and a need for great accuracy, such as those used in the medical, automotive, oil/gas and aerospace industries. A thread plug gauge measures the dimensions of a part by entering or not entering the internal thread (inside the hole of a part as required).The Go end should engage and the Not Go(NoGo) end should not engage the part. This is known as fixed limit gauging. Taperlock style (000 to 1.5 inches diameter sizes only): These gauges have a tapered shank behind the threaded portion. They are firmly pressed into an aluminum handle that has a matched tapered hole. New gauge members can be inserted into the existing handle.Unified Thread Gauges for testing Unified threads to BS 1580: Parts 1&2:2007, BS 1580: Part 3: 2007, and BS 919: Part 1: 2007 BS 1580: Pt1: 2007 specifies details of product threads. The standard includes nominal sizes and limits of size for standard threads for 1A, 2A and 3A for external threads, and 1B, 2B and 3B for internal threads in the following sizes: UNC (coarse pitch) from ¼" to 4" dia. UNF (fine pitch) from ¼" to 1½" dia. UNEF (extra fine pitch) from ¼" to 1 11/16" dia. UN (constant pitch) for 4, 6, 8, 12, 16, 20, 28 and 32 tpi for various diameters as specified. Allowances (deviation from basic size) 1A and 2A provide allowances of 30% of the effective diameter tolerances of 2A external threads. 3A is basic (no allowance). 2AG is 0.001" smaller on diameter to provide for plating to finish at 2A . (0.001” on diameter will allow for an average deposit of 0.00025”). 1B, 2B and 3B for internal threads are all basic. Before plating, threads are not designated. They are referred to as before plating and are 0.001” larger on diameter than basic size. Calibration Certificates are extra

2-56 Go No Go Screw Plug Gauges UNC Description : 2 x 56 UNC Go No Go Screw Plug Gauge Double Ended Class : 2B Unified Threads Gauges for testing Unified threads to BS 1580: Parts 1&2:2007, BS 1580: Part 3: 2007, and BS 919