Bought a portable HRC tester. Some interesting results

[Guts]

Recently grabbed one of those electronic portable HRC testers. I don't know how accurate these things are compared to the expensive benchtop diamond tipped testers, but thought it would be fun to mess with at least. Saw this style tester on the CBRx youtube channel but haven't really seen anyone else using them and got curious.

Got some interesting results to say the least and thought I'd share. Take everything with a grain of salt, as again not sure how accurate these are. HRC numbers shown are the average of 5 pokes on the tang area near the pivot if I could, sometimes on the primary bevel, or on the ricasso.

First up, the Manix Salt in Magnacut


15V Mule


15V Manix


15V Shaman. This particular knife always gave me trouble with getting a good edge on it compared to my Mule, Manix, and PM2 in 15V. 60hrc is certainly within the spec for 15V according to the Crucible data sheet though, so idk. Likely thicker geometry at play too.


Cruwear PM2



S30V PM2


S30V Sage 5


Maxamet PM2


S35VN Tenacious LW


M4 PM2


REX121 Sage 5 - errored out . This one makes sense since the max HRC the tester can handle is ~71HRC.


M398 Mule


K390 Lil Temp 3 LW. I did do one poke on the primary bevel of my K390 Endela and that showed 66.7HRC, so this result was interesting.



Just for fun, a crappy kitchen knife in unknown steel I sharpen for my mom on occasion. The burrs on this thing just do not want to go away, and I guess this explains why


Also for fun, Magnacut Sebenza 31, if accurate, certainly seem to be hitting their advertised 63-64HRC

Tried to avoid the area where the washer rides, but clearly failed. It's tricky to aim the poker on the probe since you can't really see where it'll hit.



Got some more steels I want to try on the tester, but haven't gotten around to it. Hope this was at least entertaining if not informative.

[Evil D]

Is there any way to "zero out" a tester like this? Does it come with a steel sample of a known hardness to verify any kind of accuracy? I assume there must be something like this for the high end ones.

[Deadboxhero]

Well you don't see anybody using them because that's not the right tool for the job.


Leeb impact testing is not the same as Rockwell Scale C testing, the conversion is not going to be accurate enough for us to have the conversations we want to have about X hardness vs Y hardness on knife A vs knife B etc.


Image: Testing standard for Leeb Hardness Testing (ASTM 956) the HRC reading are from a conversation and are not accurate.

I recommend reading the ASTM E18-22 and ASTM 956 for more detailed information than I have the time to share.


I think it's rude to call out Mr.CBRx but I feel he is sharing misinformation about hardness testing, he has now made it his brand to use that Leeb hardness tester to share poor HRC results. So, I feel there is no way to argue with entrenched beliefs but I hope truth finds a way to others.

Recently grabbed one of those electronic portable HRC testers. I don't know how accurate these things are compared to the expensive benchtop diamond tipped testers, but thought it would be fun to mess with at least. Saw this style tester on the CBRx youtube channel but haven't really seen anyone else using them and got curious.

Got some interesting results to say the least and thought I'd share. Take everything with a grain of salt, as again not sure how accurate these are. HRC numbers shown are the average of 5 pokes on the tang area near the pivot if I could, sometimes on the primary bevel, or on the ricasso.

First up, the Manix Salt in Magnacut


15V Mule


15V Manix


15V Shaman. This particular knife always gave me trouble with getting a good edge on it compared to my Mule, Manix, and PM2 in 15V. 60hrc is certainly within the spec for 15V according to the Crucible data sheet though, so idk. Likely thicker geometry at play too.


Cruwear PM2



S30V PM2


S30V Sage 5


Maxamet PM2


S35VN Tenacious LW


M4 PM2


REX121 Sage 5 - errored out . This one makes sense since the max HRC the tester can handle is ~71HRC.


M398 Mule


K390 Lil Temp 3 LW. I did do one poke on the primary bevel of my K390 Endela and that showed 66.7HRC, so this result was interesting.



Just for fun, a crappy kitchen knife in unknown steel I sharpen for my mom on occasion. The burrs on this thing just do not want to go away, and I guess this explains why


Also for fun, Magnacut Sebenza 31, if accurate, certainly seem to be hitting their advertised 63-64HRC

Tried to avoid the area where the washer rides, but clearly failed. It's tricky to aim the poker on the probe since you can't really see where it'll hit.



Got some more steels I want to try on the tester, but haven't gotten around to it. Hope this was at least entertaining if not informative.

[Guts]

Well you don't see anybody using them because that's not the right tool for the job.


Leeb impact testing is not the same as Rockwell Scale C testing, the conversion is not going to be accurate enough for us to have the conversations we want to have about X hardness vs Y hardness on knife A vs knife B etc.


Image: Testing standard for Leeb Hardness Testing (ASTM 956) the HRC reading are from a conversation and are not accurate.

I recommend reading the ASTM E18-22 and ASTM 956 for more detailed information than I have the time to share.


I think it's rude to call out Mr.CBRx but I feel he is sharing misinformation about hardness testing, he has now made it his brand to use that Leeb hardness tester to share poor HRC results. So, I feel there is no way to argue with entrenched beliefs but I hope truth finds a way to others.

Thanks for the info BBB. Certainly makes sense then why no one else uses these. Oh well. Was hoping it was a cheaper way to get a decent idea of HRC but guess not. Curious how far off these are from a real tester. I'll check out that info on ATSM you mentioned.

[zhyla]

Well you don't see anybody using them because that's not the right tool for the job.

What are these supposed to be used for?

[Guts]

Is there any way to "zero out" a tester like this? Does it come with a steel sample of a known hardness to verify any kind of accuracy? I assume there must be something like this for the high end ones.

It did come with a calibration block but it's in Leeb hardness, and going by BBB's reply, the conversion to HRC won't be accurate unfortunately.

[Wallach]

FWIW my Native 5 Salt in MC (which released at the same time as the Manix 2 Salt) punched at exactly 62.3 HRC, which I posted a YT video of in the MC thread.

[RustyIron]

Recently grabbed one of those electronic portable HRC testers. I don't know how accurate these things are compared to the expensive benchtop diamond tipped testers, but thought it would be fun to mess with at least.

Good on ya. It sounds like a fun contraption to fill up a Sunday afternoon with some experimentation. Even if the numbers your gadget spits out don't correspond with other hardness scales, or they aren't particularly useful in knife making, who cares? You get to play and you'll learn some things.

As I sit here at my desk, I see a stainless ID tag, a brass key, a couple aluminum parts, a rock, my fingernail--all are just begging to have their hardness tested. Have fun!

[Deadboxhero]

Who cares?

Well, regular, non-geek folks looking for HRC data aren't going to understand the nuances and they are going to take anything they see with a number dead serious regardless of the accuracy or the "why" behind best practices.

I think it's an uncomfortable truth to share but it's important for those that care about the truth to hear.

[Wallach]

To be fair, the average person also probably isn't going to be too concerned if the conversion accuracy is only a margin of .1-.2 HRC or something. If it's a significant margin, that might be a bigger problem, but I haven't seen anyone post evidence that the results are that far off either.

[Flash]

I think I’d rather have imperfect results as oppose to no results at all.
At the very least we can somewhat gauge the relative hardnesses of these steels compared to one another in the tests.

Guts, Thank you for taking the time to bring them to us.

I’m genuinely surprised by the hardness (or lack of it) on the 15v Shaman I must say.

[Deadboxhero]

To be fair, the average person also probably isn't going to be too concerned if the conversion accuracy is only a margin of .1-.2 HRC or something. If it's a significant margin, that might be a bigger problem, but I haven't seen anyone post evidence that the results are that far off either.

Yikes, the repeatability and reproducibility of the Leeb test itself is not even within "0.1-0.2rc" though.

Also, Leeb testing is NOT within the 0.5rc repeatability requirement for accurate HRC testing outlined is the testing standards at the hardness we typically see in knives.


Yes, we can discuss the conversion but we also need to discuss the test itself and with any measurement there is uncertainty of measurement even when looking at a ruler .

It is this underlying reason some hardness test methods are going to have fundamental limitations to the accuracy that can be achieved making it difficult to compare results even with a conversion.

That is why they are used for specific things.


So, it would be misinformation to say Leeb testing +/- 0.2rc accurate to HRC testing.

They are fundamentally different tests used for different things.

[Deadboxhero]

I’m genuinely surprised by the hardness (or lack of it) on the 15v Shaman I must say.

Bingo, This is why it's important to have accurate data.

People don't care about the details or accurateness, just whatever the number says without any regard.

[Steeltoez83]

Just bcuz 2 knives in the same steel have the same hrc, they can perform very differently in use. I have seen it most recently with cpm 4V. And I'm sure other testers have seen it too. Really depends on several factors but for simplicity sake I say the heat treat.

[Wallach]

Yes, we can discuss the conversion but we also need to discuss the test itself and with any measurement there is uncertainty of measurement even when looking at a ruler .

This is really my entire point. Just telling people it's not accurate "enough" and they should ignore it isn't going to work. They need to know how inaccurate the result could be even when repeated and averaged. I think the OP should take some of these blades and contact Billy over at Apex Alchemy to have them punch tested and see what the HRC actually is.

[Guts]

Might look into some third party testing if it can be done for a reasonable fee and send off one or two of the blades I tested with the Leeb tester to compare.

[Deadboxhero]

Well I did a little more than just say it's "not accurate enough" I shared the testing standards which Is extremely important reading for instance do you know what the minimum thickness and mass a test piece needs to be for accurate Leeb hardness readings? (Notice the size difference between a Leeb test block and a HRC test block?)

Well, it's outlined in the test standard.


I'm not opposed to everybody having fun and exploring things and figuring out why the wheel is in the shape of the wheel.

I just felt it was important to point out some things that are not common knowledge rather than watching folks feel around in the dark.


I am no stranger to hardness testing.

Yes, we can discuss the conversion but we also need to discuss the test itself and with any measurement there is uncertainty of measurement even when looking at a ruler .

This is really my entire point. Just telling people it's not accurate "enough" and they should ignore it isn't going to work. They need to know how inaccurate the result could be even when repeated and averaged. I think the OP should take some of these blades and contact Billy over at Apex Alchemy to have them punch tested and see what the HRC actually is.

[Wallach]

Might look into some third party testing if it can be done for a reasonable fee and send off one or two of the blades I tested with the Leeb tester to compare.

Shoot an email to Billy over at <apexalchemyyt@gmail.com>. He'll probably do it for free so long as you pay the shipping (and don't mind him making a video out of it). I'd be particularly interested to compare the results of the 15V and K390 outliers.

[Deadboxhero]

Might look into some third party testing if it can be done for a reasonable fee and send off one or two of the blades I tested with the Leeb tester to compare.

Shoot an email to Billy over at <apexalchemyyt@gmail.com>. He'll probably do it for free so long as you pay the shipping (and don't mind him making a video out of it). I'd be particularly interested to compare the results of the 15V and K390 outliers.

Well he only does one single hardness test. You'll have to convince him to do multiple tests for an average. Otherwise it's useless.

[Wallach]

Won't take much convincing, he's got no problem doing multiple punches.