Just picked up a Wilson 4JR Rockwell tester

JRB Blades

JRB Blades

Joined
Jul 22, 2013
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261
Just picked up a Wilson 4JR Rockwell tester for a screaming deal. came from a machine shop. It has all three weights attached to the back, so I should be able to test in the C scale. All the others I have looked at were missing two of the three weights. I don’t think it comes with any test blocks, does anyone know where I can pick up some of those without spending a fortune? I know I need to inspect the diamond penetrator to make sure it is still in good shape, I know those can be picked up on eBay for a good deal. If need be. So excited to get this thing and play with it. Can’t wait to test the blades I’ve been beat treating myself!
 
I got couple of well used blocks with my machine, but also HTed a piece of machined D2 (5mm thick) to use as a large testing block. Maybe you have someone around with a proven machine that could double check your results. Not ideal but beats the 100$+ per block.
 
You can buy test blocks on aliexpress for around $15-20 a piece including shipping. I have no idea about the quality.
 
I hadn't thought about ordering a hardness tester block from Aliexpress. I expect it's about the same quality as the blocks that come with the HR-150A tester. You might do a search for item #3256804311131022 on the site. $11 shipped for a 60 to 65 Rc block. Actually, this one might be better, item #3256804313673447
 
It is beneficial to have one NIST traceable test block so you know the cheapos are decent. It isn't a guarantee but does suggest the hardness will be the same all over the surface. Remember, use only one side of the block.
 
Looks like the ones on Aliexpress are the same ones as on Amazon, except they are 3X the price on Amazon. I may get a couple to see...
 
You can also get them from McMaster-Carr, I just picked one up from them the other day.
 
IIRC, JT was making test blocks suitable for our purposes.

As said, you can cut six pieces of 1/2" thick steel, sand them to 400 grit with parallel sides (surface grinder is a good idea), and HT them. Leave one as-quenched, and temper the rest at 200F, 300F, 400F, 500F, 600F. Have someone with a good tester test them three times each block and write the average hardness on the side (not on the top or bottom).
 
Hubert S. said:
Their product detail lists an accuracy of +/-5, which seems rather high. Does the NIST certificate have any details on that?
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That's how much deviation your hardness testing can have from the hardness value marked on the block, that is not denoting the hardness range of that block.

It's a common mistake people make.

That's why it's important to get a certified block so you have the most accurate representation of what the actual hardness of that block is.

Lots of people are making recommendations of making your own blocks however the consequence of that is if you're comparing test results to other testers you may be off.
 
JRB Blades said:
Just picked up a Wilson 4JR Rockwell tester for a screaming deal. came from a machine shop. It has all three weights attached to the back, so I should be able to test in the C scale. All the others I have looked at were missing two of the three weights. I don’t think it comes with any test blocks, does anyone know where I can pick up some of those without spending a fortune? I know I need to inspect the diamond penetrator to make sure it is still in good shape, I know those can be picked up on eBay for a good deal. If need be. So excited to get this thing and play with it. Can’t wait to test the blades I’ve been beat treating myself!
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Good deal man, I recommend getting a copy of ASTM E18-20 "Standard Test Methods for Rockwell Hardness of Metallic Materials" for best practices for best results.
 
DeadboxHero said:
That's how much deviation your hardness testing can have from the hardness value marked on the block, that is not denoting the hardness range of that block.

It's a common mistake people make.

That's why it's important to get a certified block so you have the most accurate representation of what the actual hardness of that block is.

Lots of people are making recommendations of making your own blocks however the consequence of that is if you're comparing test results to other testers you may be off.
Click to expand...
I'm still confused. McMaster says their test block has an accuracy of +/-5. I would have expected a test block to have a uniform hardness within a fraction of a point. The blocks I've seen have a hardness value marked to one decimal point, and I would like to believe that this is the average value of a few measurements with a small standard deviation. What exactly do they mean by accuracy? Do they mean their 60 HRC block could be anywhere from 55-65 HRC?
 
Hubert S. said:
I'm still confused. McMaster says their test block has an accuracy of +/-5. I would have expected a test block to have a uniform hardness within a fraction of a point. The blocks I've seen have a hardness value marked to one decimal point, and I would like to believe that this is the average value of a few measurements with a small standard deviation. What exactly do they mean by accuracy? Do they mean their 60 HRC block could be anywhere from 55-65 HRC?
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The actual hardness of the test block will be on the NIST traceable certificate which shows the calibrated hardness from the lab that certified it.

The testing labs hardness testing is traceable to a NIST Master block . When you buy a hardness block you are buying it within the advertised range such as "63.0rc" It will not be the exact hardness they say but should be very close for example:
block 1 at "62.91"
block 2 at "63.71"
Etc

All those are 63rc range blocks.


As I said, +/-0.5rc is a common misconception, the blocks are marked "0.5rc" because it is a requirement from ASTM for NIST traceable blocks that the blocks be marked with the maximum allowable error from E18-20 on Table A1.3.
 
DeadboxHero said:
The actual hardness of the test block will be on the NIST traceable certificate which shows the calibrated hardness from the lab that certified it.

The testing labs hardness testing is traceable to a NIST Master block . When you buy a hardness block you are buying it within the advertised range such as "63.0rc" It will not be the exact hardness they say but should be very close for example:
block 1 at "62.91"
block 2 at "63.71"
Etc

All those are 63rc range blocks.


As I said, +/-0.5rc is a common misconception, the blocks are marked "0.5rc" because it is a requirement from ASTM for NIST traceable blocks that the blocks be marked with the maximum allowable error from E18-20 on Table A1.3.
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Thank you. That clears it up somewhat, except the McMaster website lists +/-5, not +/-0.5.

1Rec10U.png
 
Hubert S. said:
Thank you. That clears it up somewhat, except the McMaster website lists +/-5, not +/-0.5.
Click to expand...

Hubert S. said:
Thank you. That clears it up somewhat, except the McMaster website lists +/-5, not +/-0.5.

1Rec10U.png
Click to expand...

I use certified Wilson brand hardness test blocks, I buy blocks from metrology suppliers, they are more knowedgeable about hardness testing than McMaster. You'll have to email McMaster Carr if you want clarification on "+/-5" looks like someone may have made a mistake.
 
From what I have gathered, +/-5 relates to the block being anywhere between 55-60. So it could be 56.5 or 58.3, etc... I don't think it means the block can be +/-5 itself. Of course I could be wrong.
 
JRB Blades said:
From what I have gathered, +/-5 relates to the block being anywhere between 55-60. So it could be 56.5 or 58.3, etc... I don't think it means the block can be +/-5 itself. Of course I could be wrong.
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Yea that wouldn't be ideal though to order a 63rc block and get a 57rc block. No thanks.

Other places its well within +/- 1rc of what you order.
 
Just picked up the Wilson 4JR. Surprisingly it came with two test blocks and 4 different anvils, so that's good. Bad news is someone swiped the diamond penetrator that is present in the pictures, but wasn't there when I went to get it. So now I have to go buy one off eBay. Oh well, $30 and a bit of a wait is OK I suppose. I emailed the auctioneer and told him that the diamond penetrator is present in the auction listing, but wasn't there when I picked it up. I'm sure they'll tell me go suck lemons, but worth a shot.
 
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