However, like your gages,
surface plates can go out of tolerance even with proper care.
If we want to measure the parallelism of one side (we'll say the bottom) to the other side (the top), we can rest the bottom on a
surface plate and compare one plane (or axis) to the other.
As rule, if you can rock any of the components on a
surface plate more than 0.005 in., then it is time for a "dusting"--i.e., grinding the surface just enough to flatten it, removing high spots or hobbed/pitted areas.
Place the cloth on a clean, flat surface, preferably a
surface plate, and then apply friction in a circular motion until the area is clean and even.
Place the cloth on a clean, flat surface, preferably a
surface plate, then apply friction in a circular hand motion until the area is clean and even.
Typical inspections were done via traditional
surface plate and other gages, methods that created problems with measuring throughput--the total time required to inspect and certify the part.
System includes a 12" manual height gage, centerline block, 12" x 18" granite
surface plate and your choice of a VDI 30 or VDI 40 toolholder block.
Course topics include Fundamentals and Linear Tools, Micrometers and Dial Indicators, Fixed Gauges, and
Surface Plate Equipment.
"A good example of this is a
surface plate. Let's look at a 24" x 36" grade B granite plate calibrated (at your site) by an outside source using a Federal level.