how does this hardness tester work?

T

tmickley

Joined
Apr 4, 2001
Messages
1,803
(Hate to post this more than one forum but I'm kinda anxious to get this thing workin...)

Got one of these with no manual, any idea how it works?
It's a Wilson Hardness tester model m-51
thanks for any help
hardness.jpg
 
Yes they work very well in fact. I have one like it. oooopps gotta run. I'll try and get back on this real quick.... sorry.

Steve
 
Tracy,

The dial closest the handle measures the pressure. The other dial measure the depth of the dent and marks that in Rockwell numbers.

The knob under the hand applies pressure.

First, turn the knob to loosen all the pressure (the pressure guage will stop going backwards.

Now put the blade on the 'anvil' and clamp down with that big screw thingy in the middle until snug.

Now slowly turn the pressure knob until the guage is at 'Set'. Do NOT go past the 'Set' mark!

Twist the hardness guage to the 'Set' spot for the 'C' scale.

Now turn the pressure knob until the guage reaches the 'C'. Do NOT go past that.

Count to 1.5

Turn the pressure knob back so you return to 'Set'.

Read the HRC off the other guage.

There you have it.

Steve
 
Thanks Steve, I appreciate it.

I tested it against the test block and it came out on the 60RC test block. I then measured my first heat treated 154cm blade and it came out at 59RC so I'm tickled about that. Now I need to go get some liquid Nitrogen and start playing with cyro and knocking out some test coupons.
 
Cool beans Tracy, what fun you'll have (until your thermocouple goes bad).

What the heck are coupons anyway.

Steve

PS Since you live in Mankato, can't you skip the nitrogen and just wait a few months?
 
Coupons are just little uniform slices of metal used for testing....and yes, it will get coldernhell soon here but I just moved SOUTH from Fargo last year where it's veryfriggincold from August through May and then two months of tough sledding. It is like the bloody tropics where I live now. We can, however, all make fun of Kile who hangs out here and still lives in Fargo when it gets so cold all atomic motion stops. It gets so cold up there in the winter, you don't grind or forge, you chip your knife out like its made of obsidian.
 
>> then two months of tough sledding

LMAO, I was born in Minneapolis and the family is there. Now I'm all soft and won't go outside if it gets below 60.

Steve
 
Here's how i use mine.

Adjust double screw to piece to be tested until there is tension, Set left dial exactly on the dot, Turn lower left knob untill dial is exactly st "Set" ( this is the minor load), Turn the right dial to zero, Turn lower left knob until needle reaches "C" ( this is the major load), Turn knob until needle on left dial is back at set, Read hardness on right dial ( this is the Rockwell "C" hardness calculated with the differences between major and minor loads). Hope this helps
 
well, now we have (I do anyway) a problem, because mine does not work either way. Mine gets consistant 60RC with the test block by:
place the piece in the anvil and tighten it snug using the double screw knob
spin left dial to 'set', spin right dial to zero, tighten lower left knob until the scale dial reaches "C", read the hardness from the right dial.
My gauge does not 'stick' to a high point showing a reading and no math (even modern math) will give me a differential reading. I have a lead on a manual copy for $15 , guess I better get one.
 
How much does something like that go for? I'd like to get one of those myself.........
 
So long as it has not been damaged you have a fine tester. I have had three of them at one time and now still have two. When in good condition and properly calibrated you can depend on what they tell you within a half point (my opinion). Honestly I do not have time to read all you and the others said here so I do not know if you have a calibration standard. If you do not you must aquire one or more. You will need one or more that are of the hardness we knife makers wish to achieve. Search for one within a few points of 60 HRc. These testers can be calibrated and kept within calibration by you so long as you have proper standards ('test blocks') and some patience. I have noticed mine not to tend to drift once calibrated but I periodically check mine against the test blocks to verify that.

P.S., I trust you received the diamond penetrator with the portable tester(?). You'll have to have that for what your testing (R C scale). And, while at it I might as well tell you not to expect reliable readings if your test piece is not flat upon the tester anvil. Just one more thing that makes knife making unique (kinda hard to find flat spots close to the edge on the stuff we make).

RL
 
blgoode said:
How much does something like that go for? I'd like to get one of those myself.........
Click to expand...
used a little over $500 on ebay, often near $900 at a used (online) machine supply. New, they run $3600. you can get a bench top for less.
 
rlinger said:
If you do not you must aquire one or more. You will need one or more that are of the hardness we knife makers wish to achieve. Search for one within a few points of 60 HRc. These testers can be calibrated and kept within calibration by you so long as you have proper standards ('test blocks') and some patience. I have noticed mine not to tend to drift once calibrated but I periodically check mine against the test blocks to verify that.
RL
Click to expand...

Hi Roger,

Do you have any leads on calibration standards at an affordable price? I need to get one for mine! :)

-Darren
 
tmickley said:
place the piece in the anvil and tighten it snug using the double screw knob
spin left dial to 'set', spin right dial to zero, tighten lower left knob until the scale dial reaches "C", read the hardness from the right dial.
Click to expand...

Tracy, in a word that method can't work. You might be getting a good reading, but it's luck.

Ricky, mentioned one point that I forgot: "Set left dial exactly on the dot". So actually the two of us are doing the same thing.

Here's how HRC testing works in short form:

First 10 Kilos of pressure is applied to the diamond creating a dent in the steel. The depth of that dent becomes ground zero. Then the pressure is increased to 100 Kilos. Then the pressure is returned to 10. Now the dent is deeper, right? How much deeper determines the Hardness. (I won't bore you with the math.)

The point is, to perform a hardness test you must set the base pressure, zero the depth scale, increase the pressure, decrease the pressure, read the scale.

Ricky's point, that I forgot is critical. So let me re-state.

1. Remove the pressure by 'unscrewing' the knob under the handle a little, just until the left dial stops spinning.

2. Clamp the blade in place with that double screw thingy

3. Turn the dial face on the left gage so the needle points at the dot (Thanks Ricky)

4. Increase pressure until the pressure gage is at 'Set. (This applies the first 10 Kilos).

5. Zero the HRC gage (This sets the starting point for measuring the depth.)

6. Increase pressure until the pressure gage is at 'C' (This increases the pressure to 100 Kilos)

7. Decrease pressure until the pressure gage is at 'Set' (This backs the pressure back down to 10 kilos.)

8. Read the hardness. (The delta between the starting depth and the finished depth.)

Does that work out?

Steve
 
Steve and Rick, your method, the correct one...:) worked after I changed the point from the 1/16th to the diamond point. Thanks for sticking with me and helping me get it right.
 
Tracy, Rejoice! Because if it didn't come with a diamond you'd be out several hundred dollars!

I didn't make sure mine had one before I bought it. Boy was I glad it was in the box!

Glad to hear it's working, pal.

Steve
 
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