Grizzly hardness test blocks, correct?

S

Scaniaman

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Jun 15, 2012
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What is your experience with the test blocks that come with the "Grizzly" hardness tester? I just started trying my new tester today and did a series of tests on the 46.1 Hrc and 62.1 Hrc blocks. The tester consistently showed appr 0.7 below those values.
Does anyone recognize this?
On a side note I tested a blade in RWL-34, where I aimed for 63 Hrc when heat treating. On that I got 62 Hrc consistently.
So seems I need to adjust the tester a little I guess? Or can I keep it simple and just add the extra 0.7 Hrc to my results when testing?
 
The tester is probably more likely to be off than the blocks, which is why testers can be adjusted. I wouldn’t necessarily place my confidence in a datasheet of RWL34, however. Compositions of a single steel vary, some datasheets are just off, furnace could be off, your cooling rates could be different than the datasheet, etc.
 
Thanks. Yes, my point with the RWL blade was just that it further seems to support that the machine needs to be tweaked a little. Ie it is showing a little lower values than it should.
 
Most hardness testers state you should have them mounted on a very rigid surface, as level as practical, and temperature and humidity constant.
If you are like me and have it mounted in your shop, and the tempremature swing is up to 40°f and the humidity swing is from 55 to 99%, I wouldn't start trying to adjust it. Just be happy it is within one point on the Rockwell hardness scale from where the test blocks say it should be.
Jim A.
 
Yeah I was thinking a little about what those parameters mean.. They aren't optimal in my shop..
 
1. Only use the tester in a clean area, keep away from grinding area.

2. Confirm your tester is level, only use your tester on a flat sturdy surface as well.

3. Confirm your weight stack is aligned and the pins on weights aren't getting hung up on the hooks.

4. Confirm the diamond indenter is fully seated and clean, same goes the selected anvil. A few throw away hardness tests on a flat scrap piece at sufficient hardness are needed after to seat either one.

5. Confirm oil carpet is fully saturated with oil to confirm all air has been displaced from dashpot. Do this by cycling the major load, without a test piece or indentor making contact. Load and unload until carpet until saturated.

6. Adjust oil needle for major load speed, choose a speed from 3-5 seconds.

7. If still lower than you can adjust the regulation plate slightly forward for increase or backwards for decrease but only after you rule everything else out.

8. Buy a quality Wilson Test Block. New with certs. This might also be number 1 :D
 
Very solid advice, Thanks. I do realize I need to get load speed down a little for one. Mine is closer to 8 s.
Where is a good source for a Wilson block?
 
There was just a recent post of how to adjust your Grizzly hardness tester. I wish I had those instructions when I bought mine. You basically need to calibrate your tester to the blocks. The blocks are accurate. I fine tuned my Grizzly hardness tester to the test blocks they provided.. Dead nuts on. Now if your oven is wrong in temp with the formula that says this temp to to this hardness then your oven is wrong. So adjust accordingly
 
DeadboxHero said:
1. Only use the tester in a clean area, keep away from grinding area.

2. Confirm your tester is level, only use your tester on a flat sturdy surface as well.

3. Confirm your weight stack is aligned and the pins on weights aren't getting hung up on the hooks.

4. Confirm the diamond indenter is fully seated and clean, same goes the selected anvil. A few throw away hardness tests on a flat scrap piece at sufficient hardness are needed after to seat either one.

5. Confirm oil carpet is fully saturated with oil to confirm all air has been displaced from dashpot. Do this by cycling the major load, without a test piece or indentor making contact. Load and unload until carpet until saturated.

6. Adjust oil needle for major load speed, choose a speed from 3-5 seconds.

7. If still lower than you can adjust the regulation plate slightly forward for increase or backwards for decrease but only after you rule everything else out.

8. Buy a quality Wilson Test Block. New with certs. This might also be number 1 :D
Click to expand...

Really solid info

Thanks and quoted for future reference
 
https://www.bladeforums.com/threads/grizzly-rockwell-hardness-tester.1697329/


LCoop said:
There was just a recent post of how to adjust your Grizzly hardness tester. I wish I had those instructions when I bought mine. You basically need to calibrate your tester to the blocks. The blocks are accurate. I fine tuned my Grizzly hardness tester to the test blocks they provided.. Dead nuts on. Now if your oven is wrong in temp with the formula that says this temp to to this hardness then your oven is wrong. So adjust accordingly
Click to expand...
 
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