Just picked up a Wilson 4JR Rockwell tester

A.McPherson said:
So I ordered a 60HRC test block, +/-5. I got a block that is 56.2HRC +/-1

Here's a pic of the certificate, and the block.

View attachment 1913335



View attachment 1913334
Click to expand...

Thanks for sharing

Yeah looks like it's within 5 HRC of the block hardness you order, that could be somewhat of a cluster if you're trying to order a 50rc block and 60rc block and they both show up basically the same hardness.



A side note on the plus or minus "tolerance"

That's the amount of hardness value difference or "error" you're allowed to you can have when you make readings with your hardness tester.

Blocks under 60rc are +/- 1.0rc

Blocks equal or greater to 60rc are +/- 0.5rc

So if you have a 56rc hardness block and your average is 0.7rc higher then you are technically within the standard (+/-1.0rc) If you have a 60rc hardness block and your hardness test average on that block is 0.7rc higher than 60rc then your tester is not within standard (+/-0.5rc) and needs to be fixed.

Source: ASTM E18-20 "Standard Test Methods for Rockwell Hardness"
 
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