wilson 4jr hardness tester help

G

Gumbi Blades

Joined
Jul 28, 2016
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Hello all! I just recently picked up a wilson 4jr hardness tester. It came with everything included, all the weights, multiple tips, anvils, the works. However it is reading 1- 2 point low on the test blocks. I know nothing about these machines or how to calibrate them. So I was hoping one of you fine folks would know more. Or if anyone has a coppy of the manual that would be great! Any knowledge and help is appreciated!
https://imgur.com/a/fqztSTr
 
I have the same tester and I believe I have the manual for it. I’m out of town right now and I’ll look for it when I get back.
 
Here's a PDF of a manual for the JR and JS series. Lots of useful info in there:

And here's another instruction manual for older testers.

Just a couple quick notes off the top of my head: heavily used or even slightly damaged brales (diamond points) aren't going to read accurately. There are also different brales for different scales, so make sure you're using one for the "C" scale.

Temperature can affect accuracy. Make sure the machine is not too hot or cold.

Make sure the machine is clean, especially around the indicator stem. When I bought might, it was all gunked up and dusty and the needle was moving very slowly and erratically. You don't necessarily want to oil the stem or completely disassemble everything, but just check it out for any dust or gunk that might keep it from traveling freely.

I normally load/unload my machine a few times just to "warm it up" and get everything moving. (without any test blocks or blades under the brale.) Just make sure the brale doesn't hit the anvil. This probably isn't necessary, but just something I do.

Also, make sure your anvil is completely clean of dust and grime (above and below), as this can affect readings too. You also want to make sure that the surface contacting the anvil face is flat and clean (and doesn't have any dents or burrs from previous tests that area proud of the surface). Tests spots shouldn't be too close together either. Around 4 or 5 point diameters is a typical spacing, if I recall.

If your testing a heat treated blade, make sure the blade is clean and free of any scale/oxidation.

I will also add that I've found that I'll occasionally get closer results if I do a second test in the exact same spot, without touching anything but my load/unload lever. I know this isn't proper technique, but I get very consistent results on my test block this way. YMMV.
 
Drew Riley said:
t I'll occasionally get closer results if I do a second test in the exact same spot, without touching anything but my load/unload lever.
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Do you mean you put the diamond tip in the same indentation as the first reading? I've never tried that, always made sure the tip was missing the first hole.
 
Check the oil in the dashpot. Adjust the dashpot so that it slows down the speed of the load. It should take 2.5 -3 seconds.

Hoss
 
I have 3JR, a JR/JS and Wilson Early Models manuals if anyone ever needs them! I took pics and put them into a zip file.

After transporting them, a tuning is needed usually, too. The index lever adjustment and dash pot adjustment will usually get it pretty close! Dash pot is supposed to be 4 seconds for the 3JR. Not sure if a 4JR is different?

3r dash pot.jpg3R lever 1.jpg3R Lever 2.jpg
 
Ken H> said:
Do you mean you put the diamond tip in the same indentation as the first reading? I've never tried that, always made sure the tip was missing the first hole.
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Yeah, Or rather I leave it in the same indentation. I don't mess with pre-load (minor load) or anything, I just take my first reading, (I.E., set minor load, then set major load for the indent, then unload for my reading), and then I just move my lever back to major load position, and unload it again, all without touching my test piece.

I'm sure there's some minor adjustment I need to be making somewhere so that it nails it on the first time, but I've tested this with my test block about a dozen times and it's always within a 1/4 point or better of my expected reading. Also, if I do it a third time, it always stays on that second reading (or very very close).
 
Hmmm. That may be an interesting test to try!
 
DevinT said:
Check the oil in the dashpot. Adjust the dashpot so that it slows down the speed of the load. It should take 2.5 -3 seconds.

Hoss
Click to expand...
This can make a significant difference. I got a 4 JR earlier this year and it was taking about 15 seconds to test. I started getting much more consistent results after I got the timing set to what the manual indicated it should be.

As others have said cleaning can help and one thing I found on mine was the weight bar had gotten slightly bent during shipping and the weight stack was hitting the back of the machine. That was causing my readings to be slightly off. Make sure you have the machine level as well. It doesn’t have to be perfect but get it as close as you can.

Another thing you need to consider is the variance of your test block. They’re generally either +/- 1 or +/- 0.5 HRC so you as long as you fall within that range you’re fine. If your machine is giving consistent readings but they’re normally 1-2 points off of the test block, that isn’t as big of a deal as the readings being scattered all over the place.
 
Mine was reading low and the indentor was chipped, so I got a new one online for like $25. Maybe something to think about and I should order a spare or two now that I think about it! LOL.
 
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