People helping each other -- No AI, no cost, no reg'n, no damn popups
(As an Amazon Associate & eBay Partner we earn from qualifying purchases)

finishing.com -- The Home Page of the Finishing Industry

-----

Difference between Ra and Rc - surface roughness

Q. In surface roughness measurement, we basically use two units Ra and Rc. Basically what is the difference between the two?

DIPAK NANDI
machine shop engineer - Ahmedabad, Gujarat, India

March 16, 2011

Hi, Dipak.

I've never heard of an Rc scale for surface roughness. The only Rc that I am familiar with means "Rockwell C scale" -- a measure of hardness.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 16, 2011

A. In the thin air of the Rocky Mountains, Rz sounds a lot like Rc.

Some very good info here: https://www.taylor-hobson.com/faq.php

(Reposted from CR4)

Willie Alexander
- Colorado Springs, Colorado

A. Ra and Rc are similar measurements with different scopes. Ra is the arithmetic mean of the deviations of crests/troughs in a surface height, whereas Rc is more isolated, measuring the mean deviation of a given band of measured surface. To simplify, Rc is a shorter measure distance.

Charles Lambert
Pool Designer - KC, Missouri
January 26, 2023

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: