4 pc Full-Ball Small Bore Hole Precision Gage Gauge Set
[MATERIAL]: The ball is made of manganese steel and the rod is made of 1215 easy-cutting steel.
Range: 1/8" - 1/2" (3mm - 13mm);
4 PCS in total(1/8''-1/5''; 1/5''-3/10''; 3/10''-2/5''; 2/5''-1/2'').
[OPERATION METHOD]: Rotate the rotary rod to make the ball head expand until it expands to the diameter of the hole. Take it out directly and measure the expansion diameter of the ball head at this time to get the size of the hole.
[HIGH PERFORMANCE]: The operation is simple and convenient. The adjustable ball head expansion structure is designed to copy the pore size, which is convenient for precise measurement.
[APPLICATION]: It is used to obtain the exact size of holes and slots, which is suitable for factories, schools, offices, and other places.