Metric Imperial 58pcs Blade US Screw Gauge SAE Whitworth 55 Degree & Metrisch 60 Degree Thread Pitch Gauge for Measuring Tool Description Features: - Made of stainless steel, rust and wear resistant, serviceable. - US thread, also known as UN thread, has a profile angle of 60 and a flattening height of H / 8, which is different from thread profile (profile angle of 55 and flattening height of H / 6). - It is useful to check the tool angle when cutting threads on a metal lathe. - It is 55 degree & 60 degree thread / screw pitch gauge gage with lock up device. - Check the angle on the thread cutting tool on the V groove of the gauge. - Metric thread is also known as international metric thread. Metric thread has ordinary thread (tooth angle 60 degree); trapezoidal thread (profile angle 30 degree); serrated thread (profile angle 33 degree); square thread, etc. (This product is suitable for 60 degree ordinary thread). - The screw gauge thread is an inch thread with a profile angle of 55 degrees and a flattening height of H / 6. G represents cylindrical thread. Note: - Wipe the measuring surface of the feeler gauge with a clean cloth, and do not measure when the feeler gauge is dirty or metal septum, otherwise the accuracy of the measurement result will be affected. - Insert the feeler gauge into the measured space, pull the feeler gauge back and forth, and feel resistance, indicating that the source value of the room is close to the value marked on the feeler gauge. If the resistance is too large or too small, it means that the clearance value is less than or greater than. - Marked on the feeler gauge. When measuring and adjusting the clearance, first select the feeler gauge that meets the clearance requirements and insert it into the measured gap, and then adjust and pull the feeler gauge at the same time, When you feel a little resistance, tighten the lock nut, and the value marked by the feeler gauge is the clearance value. _x000D_