Ames hardness tester calibration/adjustment?

Alex Dron

Alex Dron

Joined
Feb 24, 2007
Messages
328
Have model 1, circa 80s. It is pretty consistent in reading on test blocks, but always about 2 points low. I wonder if anybody knows how to adjust/calibrate it in-house. Sending to Ames is not an option because tester is too old in the first place, not to mention the cost. They don't deal with testers below S/N 12xxx

I remember somebody here mentioned the same issue and he was able to adjust, can't find the post though.

Diamond penetrator has a perfect shape under a microscope, to rule that out. Like I said the tester is accurate within 58-63 RC range for which I have the blocks, but it's annoying to remember to add those 2 points every time.

The only thing I can think of is to rotate the dial (whole unit, not just bezel) left, that will move the sensor under the arm and shorten the travel path. But the screw is dead secured, I don't want to play with it until I know for sure it is necessary.

Thanks!
 
Hi Alex, i'm in your same situation, just bought an Ames model 1 tester from ebay but the reading is way off... i was wondering if you figured out how to calibrate it yourself? I'm from Italy so shipping in US for calibration is quite impractical for me!
Thanks!
Stefano
 
Take a look at pg 2 of this pdf for the terminology I'll use. https://amesportablehardnesstesters.com/wp-content/uploads/2016/01/Ames-Std-Test-Man2016.pdf

The 'scale magnifier' on mine is a replaceable and removable piece of clear acrylic plastic. To calibrate, I simply sanded down the top surface of the scale magnifier until the unit provided a correct reading.

See pg 5, step 3 to understand how this shifts the reading. Another similar approach would be to scribe a new line on the scale magnifier.

What I suggest here is more of a hack than a true calibration. If, for example, your unit provides a correct reading at 20 RC and a high reading at 60 RC, then my solution will simply reverse the problem - it will provide a low reading at 20 RC and a correct reading at 60 RC.
 
Thank you P.Brewster P.Brewster ! i understand your hack, is quite a smart solution! :) unfortunately my model 1 is in perfect shape but probably the previous owner tried to calibrate it without knowledge... and now it is roughly off by 30 RC!!! Reading Alex post seems it is possible to rotate the whole quadrant to do a true calibration, i'd like to know if it is the way to go. And i really hope to find a solution, otherwise i've wasted some money! :))
 
Ste82 said:
Thank you P.Brewster P.Brewster ! i understand your hack, is quite a smart solution! :) unfortunately my model 1 is in perfect shape but probably the previous owner tried to calibrate it without knowledge... and now it is roughly off by 30 RC!!! Reading Alex post seems it is possible to rotate the whole quadrant to do a true calibration, i'd like to know if it is the way to go. And i really hope to find a solution, otherwise i've wasted some money! :))
Click to expand...

"In perfect shape" and "off by 30 RC" don't sound like compatible concepts to me. Something must not be right with your unit.
 
I was not able to find the answer. I'm using it as is, just have a bunch of reference blocks handy and check readings on block, testing material, block, material etc. few times in a row to get the true value. I have blocks for 58, 60, 62, 63. The problem with my tester it is not just off reading for a fixed value like 2 points, the reading seems vary from the beginning of session to the end. At start it shows expected hardness (close to reference block). 2 readings later and it shifts down. So I guess Ames trashes older testers for reason, some kept the functionality, some lost. I would expect larger models i.e. Model 4 would live longer. Mine is model 1. I also have ultrasonic portable tester (brand Novotest bought new in Ukraine couple years ago) but that things is very picky - needs ideal surface finish over 600 grit, and thickness at least 3 mm (spec says 1 mm but it is BS). It helps me when in doubt, though I would not recommend that kind of tester to any knifemaker.
 
P.Brewster P.Brewster you're right! perfect shape at least from outside... it has no dents, diamond tip is ok and the dial needle runs smooth. looks like or at least i hope the unit is just wrongly calibrate and maybe it goes above the 150 Kgs delivering wrong values, i've made various measurements and the readings do not fluctuate, are constantly off by a 30 RC. Actually i'm away from home so cannot take pictures, but the needle in rest position is not laying horizontal like in all the photo i can find online, it is a 30 degrees above normal position... this is why i suppose the whole dial is rotated.
 
Alex Dron Alex Dron thank you very much, my unit is around 14XXX but is not off by just 2 points, so is impossible to compensate every reading by 30 RC! I had also looked at those ultrasonic tester and i'm glad i did not had bought! just to know have you tried to rotate the dial as you proposed in the first post? If yes how did you do?
 
It’s not uncommon for the first one or two readings to be a couple points off the rest of the readings. If the values continue to change after that you might have a bigger problem.
 
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I don't believe the rotation would help in my case and I haven't touched it - see my post above, it is not always 2 points off for me and rotation won't help, probably only makes it worse.
But for constant 30 points shift - it might work. Mark the original sensor position. There is a bolt head in the center of dial's back cover, could be hex, or some tamper proof like spanner drilled. Unscrew a bit, maybe a half turn, and try to rotate the dial so sensor moves towards the arc. 5-10 degrees. Fix the nut and measure, see if it makes a difference.
 
Thank you very much Alex, your case is clearly different and understandably you haven't rotate the dial. I'll make some test with mine and hope to solve it and don't screw it up!
 
I have the same tester. One day it started giving bad readings. I said the heck with it and took it all apart. The center screw can loosen and you can turn the whole assembly. Not the bezel the whole thing. I just loosened mine, moved it and tightened it and did some tests. If it was closer I’d keep turning it till it was reading right. If it was more off then you need to turn it the other way. Seemed to work for me. YMMV
 
I have a rams rockford tester that I was not happy with and JT posted how it could be because it's in a shop that fluctuates , a constant environment could make a difference. I moved it to the house and it works pretty good now. Just throwing that out there.
 
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