Rockwell Hardness Tester Opinions

M

Marc Cooper

Joined
Apr 7, 2019
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60
Hey All

I have been looking for a reliable and user friendly Rockwell Hardness Tester and I found this large bench style tester for $1600 here in Canada. It is an HR150A 3R Rockwell Hardness Tester like the one shown in this link:

https://www.google.ca/amp/s/www.acc...330-hr-150a-3r-type-rockwell-hardness-tester/

It comes with the 3 testing tables, diamond penetrator, ball penetrator and 3 test blocks.

Since I am new to Hardness testers, I wanted to make sure this is a good system for testing Knife Hardness.

Does anyone know if this will do the job? I'm also open to other options for good quality testers.
 
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One thing to keep in mind is anvil size, guess this company calls them tables. With blades I find that the smaller anvil gives more repeatable results. My small one is like 5/8” diameter, It’s basickly just a post. if the blades have any and I mean any bow or the surface is not flat and that surface ends up facing the anvil you will get false readings. The tester will load up the pre load fine but once you apply the 150kg test load the blade will flex down. Hardness testers work by measuring the depth the penetrator is pushed into the surface between after the preload is set.
 
The Rockwell you are looking at is top of the line. If you buy it, you will have to have it serviced and re-calibrated by a good hardness tester service provider. This is recommended any time you physically move a tester and recommended every year or so. It is a good practice to use the smallest diameter anvil for repeatable results. Knife blade size stock would only need a 1/4 to 1/2 inch anvil tops. This ensures you have flat contact with the anvil and no spring effects.
 
Ok, I'm going to ruffle some feathers here, I'm not trying to take over this gentleman's thread, but I talked to a knifemaker about this very topic. I won't say who, but you'll get hundreds of hits if you Google his name. He told me not to obsess as much about Rockwell hardness as much as some guys do. Do you guys really worry that much about it? If you make a chef knife that you wanted to be 60 and it turns out 58, you through it in the garbage?
Thank you.
 
First, the HR150A is a good tester. I have one and it works well- just not below about 40f.
Second, no RC is not the be-all end-all statistic... much else will come into play such as intended blade use, geometry, steel type, and I'll just mention geometry again, lol. It is however an important thing to know, and much better not to have to guess.
 
kmf600 said:
Ok, I'm going to ruffle some feathers here, I'm not trying to take over this gentleman's thread, but I talked to a knifemaker about this very topic. I won't say who, but you'll get hundreds of hits if you Google his name. He told me not to obsess as much about Rockwell hardness as much as some guys do. Do you guys really worry that much about it? If you make a chef knife that you wanted to be 60 and it turns out 58, you through it in the garbage?
Thank you.
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Nope, but if it turns out 50, I know I have an issue somewhere and I have a chance to address it.
 
If I do a batch of hardening of say 100 knives, I test from 5 to 10, is good to know the hardness of random samples even after doing the same time and time again, reassures you, the steel and the process.

I bought mine used, this was my calibration procedure:

Made about ten O1 biscuits of 10mm thickness (0.4") left 3 as they came out of the oven, 3 at 61 and the rest at 58 RC following only the Bohler K460 datasheet temperatures, then surface grinded all of them on both sides and measured 4 times each one writing with a sharpie the average value. Then passed these biscuits to colleagues with RC testers and asked them to do the same (always using the same side of the biscuit) Then I verified and made corrections to meet the community readings. Worked very well, I had the chance of testing one of them on certified RC tester and the readings were within tolerances +/- 1RC

Pablo
 
kmf600 said:
Ok, I'm going to ruffle some feathers here, I'm not trying to take over this gentleman's thread, but I talked to a knifemaker about this very topic. I won't say who, but you'll get hundreds of hits if you Google his name. He told me not to obsess as much about Rockwell hardness as much as some guys do. Do you guys really worry that much about it? If you make a chef knife that you wanted to be 60 and it turns out 58, you through it in the garbage?
Thank you.
Click to expand...

Now let me ruffle some feathers. If you have designed a knife to preform optimally at 62rc and it’s 58 then it will suffer. Some steels have hardness ranges where thy really excell and also ranges where thy suck. Some steels will come with warnings from the manufacture stating high brittleness at XX hardness. And other steels will have best corrosion resistance at XX hardness. I equate it to building a house, your hardness is your foundation. It seams that most of the time when this topic comes up it’s asociated with a maker that’s either lazy or unexperanced. Im not saying you are either of thoes but be very cautious in wrighting off somthing as important as hitting the hardness you need. If customers wanted average preforming knives thy would buy production. Thy come to us bevause thy know we will pay special attention to every little detail. It becomes a slippery slope that is easy to loose track of. To give you an idea the difference between 58 and 60rc is about 20,000psi in tensile strength. After you get experance you don’t obsess over it as much because you know it’s right where you wanted it. This is more common with carbon steel then stainless.

But you have to remember this comes from a guy who’s business is hitting hardness numbers people (you guys) want. I hardness test every blade at every step. You would be suprized at the swings in hardness I have seen. I have seen identical alloys heat treated at the same time have a 3rc difference. It all evens out in the wash but you could be quite a bit off if you just blindly falow a heat treat schedule.
 
Unless you have money to burn, find a local machine shop and ask to use theirs. if not, ask What level of calibration was done to the tester and is still in calibration(usually a 6 to 12 month calibration cycle)? What is the tolerance of the tester? Unless you are using "Standard" level equipment, +/- 1 unit would be the best expected.
What is the tolerance of the calibration blocks? do they have documentation? anywhere from +/-1 to 3 is what is sold. expect to spend $200 for one Rc60 +/-1 test block
How is the calibration block being used? If you test too close to a previous test, your results are going to high. When one side was covered with test marks, did you turn it over? if you did, your results are skewed, because the reverse side does not have the same surface finish. How close to the edge are you testing. too close and results are skewed. How thick is material being tested, if less than 10x the test hole depth, results skewed. is spot being tested flat and 90* to the test arm, if not more error
So here we are, Jason and Scott have the same model tester, calibrated by same calibration lab, same test blocks. Jason tests a knife and gets a reading Rc64. Mails Scott the knife which he tests and gets a reading of Rc60. Who is right? Knife and the testers are sent to third party who has higher tolerance equipment and the blade measures Rc62. Scott's tester was -1 and the calibration block was -1. Jason's tester and cal block both read +1. So both were right.
the old sailor
 
Marc Cooper said:
Hey All

I have been looking for a reliable and user friendly Rockwell Hardness Tester and I found this large bench style tester for $1600 here in Canada. It is an HR150A 3R Rockwell Hardness Tester like the one shown in this link:

https://www.google.ca/amp/s/www.acc...330-hr-150a-3r-type-rockwell-hardness-tester/

It comes with the 3 testing tables, diamond penetrator, ball penetrator and 3 test blocks.

Since I am new to Hardness testers, I wanted to make sure this is a good system for testing Knife Hardness.

Does anyone know if this will do the job? I'm also open to other options for good quality testers.
Click to expand...
You can buy the exact same unit from grizzly for 1100.00 shipped. It's a great tester and there are lots of folks on this forum that have spent a lot of time tinkering with them. You can calibrate it yourself, so don't worry about that. Probably won't even be needed, they pack them pretty well.
If you are patient you may be able to get one second hand if you keep an eye on craigslist and ebay. I got mine for 400 bucks.
 
Thanks for the input everyone.

My main concern is that I live in Newfoundland and there is nowhere to get steel harness tested and no one with experience calibrating these machines.

How hard are they to calibrate? It comes with the A, B and C test block but I'm new to calibrating Hardness testers.
 
Marc Cooper said:
Thanks for the input everyone. My main concern is that I live in Newfoundland and there is nowhere to get steel harness tested and no one with experience calibrating these machines. How hard are they to calibrate? It comes with the A, B and C test block but I'm new to calibrating Hardness testers.
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google machine shop and you will find a bunch in the St. John's area. for calibration check these folks: Cahill Instrumentation in Mt. Pearl, phone is 709-747-3800
If buying a used machine, I would have it verified and calibrated by a certified lab that will verify that everything is working properly. A new machine should come with a calibration certificate.
Go here https://www.buehler.com/literature.php#TechNote and they have articles about use, care and feeding of hardness testers.
for how to use try https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication960-5.pdf our US tax dollars at work
enjoy
the old sailor
 
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JTknives said:
Now let me ruffle some feathers. If you have designed a knife to preform optimally at 62rc and it’s 58 then it will suffer. Some steels have hardness ranges where thy really excell and also ranges where thy suck. Some steels will come with warnings from the manufacture stating high brittleness at XX hardness. And other steels will have best corrosion resistance at XX hardness. I equate it to building a house, your hardness is your foundation. It seams that most of the time when this topic comes up it’s asociated with a maker that’s either lazy or unexperanced. Im not saying you are either of thoes but be very cautious in wrighting off somthing as important as hitting the hardness you need. If customers wanted average preforming knives thy would buy production. Thy come to us bevause thy know we will pay special attention to every little detail. It becomes a slippery slope that is easy to loose track of. To give you an idea the difference between 58 and 60rc is about 20,000psi in tensile strength. After you get experance you don’t obsess over it as much because you know it’s right where you wanted it. This is more common with carbon steel then stainless.

But you have to remember this comes from a guy who’s business is hitting hardness numbers people (you guys) want. I hardness test every blade at every step. You would be suprized at the swings in hardness I have seen. I have seen identical alloys heat treated at the same time have a 3rc difference. It all evens out in the wash but you could be quite a bit off if you just blindly falow a heat treat schedule.
Click to expand...

Hallelujah, someone FINALLY said it out loud!
 
OK, you're not building spaceships here. If you get a tester and it's consistently hitting the right numbers with your test blocks you're good. If it is off a point or two, you're good as long as the readings are consistent, you know to add or subtract that point from your results. If you want to calibrate it yourself K Ken H> put together some detailed instructions on how to do it yourself. I have a copy of the directions, DM me your email and I'll send them to you.
When you start building spaceships please follow the above advice and have it professionally calibrated and certified on a regular basis.
 
Here's the link on Grizzly's HR-150A tester for $995 USD,
https://www.grizzly.com/products/Grizzly-Hardness-Tester/G9645
it's a good item. Not cheap, but less than some other places. Grizzly specs the weight as "approximate net weight: 195 lbs." I can't imagine it's much over 100 lbs, it will still have to go freight per this statement "We ship non-freight items (items less than 66 lbs.) to Canada via i Parcel. Items over 66lbs. are shipped by UPS Standard or UPS Freight." Shipping to USA is $100 making it $1100 cost to USA, but that's $1450 in Canadian. Is your $1600 Canadian? If so, that's $150 much more than we're paying here in USA.

Newfoundland area is a long way and could make a difference in shipping cost.

Good luck - I looked for a used Rc tester for a few months, gave up and ordered a Grizzly a few years back, and it was the same price as now... or was it $1000 shipped?
 
Ken H> said:
Here's the link on Grizzly's HR-150A tester for $995 USD,
https://www.grizzly.com/products/Grizzly-Hardness-Tester/G9645
it's a good item. Not cheap, but less than some other places. Grizzly specs the weight as "approximate net weight: 195 lbs." I can't imagine it's much over 100 lbs, it will still have to go freight per this statement "We ship non-freight items (items less than 66 lbs.) to Canada via i Parcel. Items over 66lbs. are shipped by UPS Standard or UPS Freight." Shipping to USA is $100 making it $1100 cost to USA, but that's $1450 in Canadian. Is your $1600 Canadian? If so, that's $150 much more than we're paying here in USA.

Newfoundland area is a long way and could make a difference in shipping cost.

Good luck - I looked for a used Rc tester for a few months, gave up and ordered a Grizzly a few years back, and it was the same price as now... or was it $1000 shipped?
Click to expand...

UPS shipping will F him in the ear for "Brokerage charges"


Also look at KBC Tools, Travers Tools, used equipment auctions / liquidations.

Used machinery dealers - hardness testers are much less commonly wanted than lathes, mills, forklifts and such.
 
Oh, I know the shipping will be expensive. I was trying to show he's not paying all that much more in Canada for the HR-150A at $1600 (if it's Canadian) than we are at $1100 USD.... only $ 150 or so more.
 
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