Metric thread diameter is in millimeters, such as 6,8,10,12,18,20 mm and so on pitch in millimeters, such as 0.5,0.75,1,1.5,2,3, etc.
inch thread diameter is in inches, (equal to 25.4 mm per inch) such as 3/16,5/8,1/4,1/2, etc., so the metric caliper gauge of the outside diameter readings often with irregular decimal.
The inch pitch is represented by how many teeth each inch is contained. Set the caliper to 25.4 mm, a-foot-tip alignment screw thread, another ruler, such as alignment screw thread is inch thread, such as the screw thread should be metric threads.
When measuring the pitch, it is best to put the teeth tip of the thread on the white chalk, and the printing on the chalk is clearer and easy to measure. Measurement of metric pitch should be measured for a length, such as 10,15,20, MM, and so on, counting the number of teeth, calculate the pitch.
in inches for the unit specifications for the thread of inch, such as: G1. Metric units of MM specification for threaded threads, such as: M30.
The inch is a inches (2.54 cm) of the number of teeth to be determined, generally 55 degrees. The metric is the spacing between the two teeth is how many mm to set the pitch, generally 60 degrees angle.