Rockwell Tester Questions

[SHostetler]

Hi All,
Purchased a Rockwell tester recently and just got it calibrated.In reading how to conduct the tests I came up with a couple of questions.

1. How parallel do the 2 sides have to be? This is in reference to testing on the blade bevels. Would testing on the bevels give the same results as testing on the ricasso?

2. What kind of surface texture is needed for an accurate test? This is in reference to the grit of the belt last used. Would a 60 grit finish test the same as a 600 grit finish?

Thanks in advance,
Steve Hostetler

[Don Robinson]

The piece should have parallel sides in order to get an accurate test.

I think the surface should have at least a 220 finish.

[SHostetler]

Thanks don. I kind of thought that the bevels would be problematic. Should I just avoid the bevels and test at the ricasso/tang junction? Or is there a way to test the bevels, say a shim or perhaps just accept a less than perfect reading? Any thoughts about how much the bevels would distort the reading?

Thanks
Steve

[Doug Lester]

What I would suggest is that you test both a flat area, like the ricasso and the bevel and compare the readings to see how much they differ from each other. Of course, you could run into problems with a shallow hardening steel as these areas could form different products of austinite due to the different rates of cooling between that thick and thin sections.

Doug

[Don Robinson]

Originally Posted by SHostetler

Thanks don. I kind of thought that the bevels would be problematic. Should I just avoid the bevels and test at the ricasso/tang junction? Or is there a way to test the bevels, say a shim or perhaps just accept a less than perfect reading? Any thoughts about how much the bevels would distort the reading?

Thanks
Steve

I always test on a flat area. My blades are all hardened all the way thru. If you test on the bevels how will you hide the marks?