It depends on the surface finish of the workpiece. For machined surface a magnetic base dial indicator is used. For rough or un-machined surfaces a surface gauge is used.
Ra 3.2 basically mean the surfaces must be machined to a tolerance of 3.2micro metres > Ra 3.2 would mean a standard finish on a lathe or miller ie not a deliberate finishing (slow speed) cut.
micro means 10 to the -6 inches so for example 32 microinches would be 0.000032 inch. With respect to surface finish it is basically a measure of the height of the "peaks and valleys" of the finish of a surface. There are different ways to measure this (RMS, etc.) but that is basically what it means. So for example a 125 microinch finish is a typical machined fnish for metals but a 32 is much better and would be called out where sealing surfaces may be needed.
Machined - 2006 V is rated/received certificates of: USA:R
Yes. The type of finish on the machined component's surface could be crucial to the quality of the type of coating or plating required.
Means to finish painting a drywall.
To explain why your verb is what it is.
I finish
Finish
It means finish cooking your meal or dessert in the oven!!!!
I finish
finish