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Surface Roughness (Ra) vs. Abrasive Grit Number

Surface Roughness (Ra) vs. Abrasive Grit Number

Surface Roughness (Ra) vs. Abrasive Grit Number

I'm having trouble locating a table correlating these two items I feel I can trust.
My interest is for steels soft or hard, using SiC abrasives, emery cloth, even Scotchbrite.
Thanks in advance for any data or links.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: Surface Roughness (Ra) vs. Abrasive Grit Number

The only thing I have that is anything close is from the "Society of the Plastic Industry", it is a mold finish chart that relates Ra values to the surface finish material used on the molds.
i.e. if you are looking for a plastic part with an Ra of 4 to 5 you would want to finish your mold surfaces with a #400 grit paper, Ra of 38 to 42 use a #320 grit stone, etc.

RE: Surface Roughness (Ra) vs. Abrasive Grit Number

Table 3 from the link provided by XL is similar to what we use.
For example, when we want a #4 finish (which we consider that about 20-25 microinch Ra) we use 180 grit dry or 120 wet.
To achieve finishes <10 microinch we polish in stages and finish with wet 320.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Surface Roughness (Ra) vs. Abrasive Grit Number

Further googling located this and this.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

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