Anyone know what the recomended final RA is when lapping plates?



Thanks



Greogry

bump

I'm feeling a little dense right now. What is RA? The final compound for finishing a surface?

http://www.jjjtrain.com/vms/engineer...ce_finish.html





Ra is the arithmetical mean roughness of a surface. Surface roughness values, including Ra need a dimension to be interpreted. The common unit for machining applications in the US is microinch (millionths of an inch). Metric values would be microns (millionths of a meter) or nanometer (billionths of a meter) for polished surfaces.





The average roughness, Ra, is expressed in units of height. In the Imperial (English) system, Ra typically expressed in "millionths" of an inch. This is also referred to as "microinches" or sometimes just as "micro" (however the latter is just slang). In the metric system, Ra is typically expressed as "millionths of a meter" also called "micrometers" or "microns".



- Mark Malburg, Ph.D.

Chairman ASME-B46.1 "Surface Texture"