How To Try out and buy a used hardness tester?

Jan H. said:
Hi,

that looks like an awesome acquisition, at an absolutely incredible price for the actual value you got! Not only perfect working condition, all imaginable bits an pieces, an original manual (that one almost amazes me the most), and a museum-piece history as well!
Congrats!

Mine is a good bit younger, a Karl Frank from 1968, so a good 25 years between them, but not much change in design at all - why change anything if it works?

I had a look into the gutts of my machine, the 3 weights in the back on the pendulum are (from top to bottom) the ones labeled with 62.5 kp, 100 kp and 150 kp. That is (at least with my machine) the weight combination for measuring Rockwell C.

Big cheers

Jan
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Thanks, in the end I got just the Karl Frank and paid 270 Euro.

Today the readings were consistently 2 or 3 hrc lower (on the good block and knives). I am sure the machine needs some tlc, new oil and the setting you mentioned. Maybe a new indenter as well (I will go for Chinese and upgrade if necessary).

I need to sort out the manual, cause it's falling apart. I will probably put it online in case some pour soul is looking for it or it might serve someone.
 
Scaniaman said:
Makes sense. I freeze at -43 and get 62 Hrc with that program. I can get both CO2 and LN2, but -43 is just more practical to me.
Click to expand...

I get it, I had to run during work time on Friday to get the dry ice and by the time I did the HT half of it was gone.
 
Scaniaman said:
If ever decide to go colder I think a CO2 gas tank with a snow cone, or LN2 looks most practical.
Click to expand...

Yes, but that's $$$. I got the dry ice at 2,50 per Kg, and they gave me the weight once over for free. :)
LN2 is awesome though.
 
J Jan H. do you maybe now what the function/setting of this screw is? If I tighten it, it pushes the indenter out of true. I guess it needs be only as tight to prevent indenter moving sidewise and keep it in 90 degrees to the test piece?
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Here is a pic from a newer tester
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Did your manual come with pictures in description?

Here just to show how mine looks :)
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FredyCro said:
J Jan H. do you maybe now what the function/setting of this screw is? If I tighten it, it pushes the indenter out of true. I guess it needs be only as tight to prevent indenter moving sidewise and keep it in 90 degrees to the test piece?

Here is a pic from a newer tester
...
Did your manual come with pictures in description?

Here just to show how mine looks :)
...
Click to expand...

Hi,
I have the same screw, but never had to touch it. I assume it is there to accomodate for differently sized indenter adapters (Brinell/Vickers/Rockwell,...). If it changes the allignment, I would - as you said - just make sure it is the right allignment.
My Manual is text only, too.
One more thing: make sure the table where you put your test pieces on beneath the indenter is dead-flat, clean of any dust and sits rock-solid and level in its place on top of the big screw. Dust particles and also oil residue on that table can mess with the measurements!

Cheers!
 
FredyCro said:
Yes, but that's $$$. I got the dry ice at 2,50 per Kg, and they gave me the weight once over for free. :)
LN2 is awesome though.
Click to expand...

Once you buy the dewar, it's alright I think. When doing HT seldom like me, you could just pick up a litre or two for that occasion. A CO2 tank you would keep on a long term lease for maybe half a euro per day. Still, -40 freezer is so practical...and chasing an extra point on the Rockwell scale wont make or break how good my knives are in their total I guess
 
Jan H. said:
Hi,
I have the same screw, but never had to touch it. I assume it is there to accomodate for differently sized indenter adapters (Brinell/Vickers/Rockwell,...). If it changes the allignment, I would - as you said - just make sure it is the right allignment.
My Manual is text only, too.
One more thing: make sure the table where you put your test pieces on beneath the indenter is dead-flat, clean of any dust and sits rock-solid and level in its place on top of the big screw. Dust particles and also oil residue on that table can mess with the measurements!

Cheers!
Click to expand...

Thanks, yeah, I was surprised with the different readings, but they are at least consistently off. I will clean the table and give it a clean with a 600 grit paper on a surface plate.

I will also change the oil and recheck the weight stack.
 
Cleaned up the tables, added oil (nice consistent lever action) and played with the setting screw. Now within the spec of the original bloc (64,2 +/-1) and knives are testing consistently (like 15-20 tries per knife) . For the fun I also tested some knives that I had HT and they tested lower then speced. Happy to do the HT and test by myself in the future. Thanks again to all of you!

I will report on the Chinese indenter.
 
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