Certified Rockwell C sample...

[Kevin R. Cashen]

My test block is from Westport. Theirs is maybe $82 I think? They tell you +/- 5 points when you order it. Then it is etched on the side of the block with the actual hardness and a range of +/- 0.5 points. They do send you a certification sheet with all their readings on it.

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I see you have one of the HR 150 units, good call on getting a better block, the Chinese ones that come with it are pretty rough affairs. I used one of these testers for around 10 years, solid unit so long as you check it. Once it went out and the pattern scattered it was done. But, to be fair, I did use it to death.

 

[Gliden07]

Ted I bought a new old stock test block on Ebay still was 50 bucks. And all the time i searched! After that the 75 is well worth it. And on top of that i got mine in C scale and my tester is N so i have to convert it!

 

[C. Killgore]

I see you have one of the HR 150 units, good call on getting a better block, the Chinese ones that come with it are pretty rough affairs. I used one of these testers for around 10 years, solid unit so long as you check it. Once it went out and the pattern scattered it was done. But, to be fair, I did use it to death.

Yes sir! I believe it was you that recommended I pick up a better test block years ago on the hype free forums. Glad I did. Mines been doing pretty good for the last 5 or 6 years. Hopefully it lasts quite a while longer. But I'm pretty slow about making knives so it doesn't get used too much.

 

[Smallshop]

Guys...thanks for all the input. Here is the response from Mcmaster carr:

Bill at McMaster went out and actually took a pic of the cert....So yes...it has multiple tests on a given sample...And the actual test results.
The way the description is worded online is very unclear...the pic here is indeed worth a thousand words!

company has a US address...SPI bocks...Swiss precision Instruments...were from China...not bad probably...but I have never gotten anything cheesy from McMaster Carr...And MSC still has yet to reply to my question...

 

[KenH]

I've always had good results dealing with McMaster-Carr. Their shipping costs are usually VERY reasonable and they ship fast.

Ken H>

 

[springer82]

This is not even close to what I am talking about...and yes...i do have an idea of what I am asking...

You can calibrate your own equipment for non-aerospace non-medical (non-regulated industries) work...'bout every company does it.(anytime you check a mic on a gage block this is what you are doing)

I'm under no legal obligation to professionally calibrate equipment I use to offer a company "certificate" of hardness. My knives are not being used in a capacity such as a medical instrument or a component on a sattelite. It is merely a matter of interest to the end user "how hard/tough is this blade" and a matter of "are my heat treat and temper recipes actually giving me what I want".

The minute you have calibrated your machine using a certified test coupon you are more than good for the trade we are in. A rockwell tester is a very basic machine...the certified test piece will do the trick....for a couple years most likely...until the divots on the one side make it hard to find a fresh spot to test on...lol.

I simply want to use a certified test piece to calibrate my own tester so I am not guessing where I am really at.

To start, I apologize if I rubbed you the wrong way. That was not my intention. I guess I've been doing this to long. I sign FDA paperwork every day regarding equipment. Your lucky to have that piece of equipment. That's way to much for me. I hope your test blocks work well for you!

 

[C. Killgore]

Cool, I order lots from McMaster. Always seems to be pretty good quality stuff and it gets to me the next day.

Seems a little weird that all 5 readings were the same? Maybe not, not an expert in this stuff.

Mine showed a little variation. Maybe they just round it off.

 

[Smallshop]

MSC replied today and they also do a few test on the block. Their cert is NOT traceable to NIST. I already had ordered the mcMaster block yesterday.

Thanks for all the input guys...$75 is not really too much when thinking about calibrating a piece of test equipment....but when you have a heat treat furnace and a surface grinder and a chop saw...well...you know...lol...feels like, "Heyyyy...wait a minute....."

 

[Andre Grobler]

Guys...thanks for all the input. Here is the response from Mcmaster carr:

Bill at McMaster went out and actually took a pic of the cert....So yes...it has multiple tests on a given sample...And the actual test results.
The way the description is worded online is very unclear...the pic here is indeed worth a thousand words!

company has a US address...SPI bocks...Swiss precision Instruments...were from China...not bad probably...but I have never gotten anything cheesy from McMaster Carr...And MSC still has yet to reply to my question...
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This uncertainty they stipulate is roughly half of the last digit, well it is a little less i am assuming because they have 5 exactly the same as last count... actually when you measure things the last significant digit is the one you are sure of, so in this case they are sure of 61, and not so sure of the 0.5 - if they hide the last digit to make it look more uniform or some other reason it may be calculated... but that .23 is kinda like a standard deviation but not... so you can say they are quite sure it will be between 61.3 and 61.7 ish...

 

[Smallshop]

Andre...that is how I understand it also.