Ultrasonic contact impedance hardness tester

I

IanF

Joined
Apr 22, 2017
Messages
9
Hi there guys

i am looking for a suitable hardness tester of checking my heat treat results and through my research have come across ultrasonic contact impedance devices. These are advertised as being able to test very thin section metal (down to 1mm) and various shapes ( not just flat). If true these would be very handy and they re small and portable. An example of one is shown here http://novotest.biz/portable-hardness-novotest-t-ud3/

I know the general advice is to look at a benchtop impact hardness tester with preload but I can’t find much on these UCI machines. Does anyone have any experience with them for knives. My main use will be for smaller blades like folders.

I am based in Australia so our second hand market for these kind of devices is quite limited compared to what I see in the US. I do have my eye firmly on the used market for a good condition benchtop model but am having to think beyond this given the rarity.

thanks
Ian
 
We looked at them and you will find thy are not very accurate
 
Did anybody see a price on that type of hardness tester? The spec say 2HRC for what that means (no way to tell if that's a valid number or not). If that's ± that's a pretty big range.
 
Thanks JT and Ken

JT - your comment is valuable in that I am sure if these were as good as they sound someone servicing the knfe industry would have found a way to make them work for our hobby. That seems to not be the case and I guess when something sounds too good to be true it probably is!

Ken - i agree that if +/- 2 HRC is the accuracy it isn't great from what are not cheap machines. Hardness files should get you within 5 HRC so I would hope that these were a lot better for the cost.
 
Yep, the HR150A is spec'd at ±1.0 which still isn't really all "that" good. Means when reading 60.0, the actual could somewhere between 59.0 and 61.0 - I think it's actually better than that since the repeatability on a test block is certainly better than ±1.0
 
Thanks Ken

In reference to price - cost I was given for the linked product in my original post was around $1800 Austraian dollars so around $1500 US.
 
We are thinking of producing hardness blocks. As funny as it sounds it a common test at work for all kinds of materials. Whack a corner of one material into the corner of another material. The corner that dents is softer lol. So we are thinking of marking sets of surface ground hardened whack sticks so to speak with a spacing of maybe 2rc between each one.
 
JTknives said:
We are thinking of producing hardness blocks. As funny as it sounds it a common test at work for all kinds of materials. Whack a corner of one material into the corner of another material. The corner that dents is softer lol. So we are thinking of marking sets of surface ground hardened whack sticks so to speak with a spacing of maybe 2rc between each one.
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I was just going to suggest these, there was someone selling them couple of years ago. There is a vid on YouTube that demonstrates how to use them. IMHO they should cost about the price of the hardness files but be in the hardness range more usable to the knifemakers (56/58—64/66 sounds reasonable).
With a reasonable length they could be resharpened and would easily last you a lifetime.
 
FredyCro said:
I was just going to suggest these, there was someone selling them couple of years ago. There is a vid on YouTube that demonstrates how to use them. IMHO they should cost about the price of the hardness files but be in the hardness range more usable to the knifemakers (56/58—64/66 sounds reasonable).
With a reasonable length they could be resharpened and would easily last you a lifetime.
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The amount of "Whack" would be subjective to each individual which in turn would lead to huge variance in accuracy.
 
Busto said:
The amount of "Whack" would be subjective to each individual which in turn would lead to huge variance in accuracy.
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In the test video there was no wacking, bacisally it was like running thick (like 1mm) edge of knife against same thickness edge of the tester. The one that bites in or shows a mark is softer.
I don't have any personal experience, but maybe someone else has, I guess it would include some soft touch and feel how to use (like a hardness file test).
 
JTknives said:
We are thinking of producing hardness blocks. As funny as it sounds it a common test at work for all kinds of materials. Whack a corner of one material into the corner of another material. The corner that dents is softer lol. So we are thinking of marking sets of surface ground hardened whack sticks so to speak with a spacing of maybe 2rc between each one.
Click to expand...
I’d suggest looking at black dragon forges hardness chisels, much less subjective than how hard to whack something. I use those for testing at home, I do a lot of forged pieces with the scale being left on the flats so not way to use an hardness tester accurately on those so I’ve found the chisels work great in those cases or if I’m leaving mill scale on the flats of a stock removal knife. The set I have is made from A2 and has 4 chisels at 58-60-62-64. I believe they were heat treated at Peters. It would be great if someone made these in every point of hardness from 55-65
 
I would argue that the speed of whacking is not as important as you might think. Corner to corner the softer material will yield first no matter the speed of the whack. Not saying it would be the most accurate thing in the world but I feel it would get you within an practical range.
 
Here the vid. It looks pretty convincing to me. Better than files, not as good as a hardness tester.
 
These would be Ok I suspect for the hobby maker, but I would not hang my reputation on a chisel vs a Rockwell hardness tester with certified test blocks. Cheap is never Better as the saying goes "You get what You pay for".
 
Busto said:
These would be Ok I suspect for the hobby maker, but I would not hang my reputation on a chisel vs a Rockwell hardness tester with certified test blocks. Cheap is never Better as the saying goes "You get what You pay for".
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That sums it up. I am on the hobby side of things and I upgrade as I go. Sometimes you know there is a better tool for the job, but you use what you have.

I hope the op will find a used unit for a good price (keeps your eyes open and be patient).
 
I'm a tool guy, but lets be realistic here. Probably less than 1% of knifemakers here in the USA have a hardness testing machine or tool ( file, chisel, whack stick). Worldwide, it is probably less than .01%.

People made knives for 1000 years without hardness testers, files, or chisels. They tested their blades to see if the hardness was good.

Today, we are lazy and want some machine (or some other person) to tell us if the knife is good. However, merely knowing the hardness isn't going to tell us if a knife is good, or the steel was properly hardened and tempered.

I'm not saying that having a tester isn't good .. it is great ... but it isn't the be-all and end-all of knifemaking.
 
Stacy E. Apelt - Bladesmith said:
I'm a tool guy, but lets be realistic here. Probably less than 1% of knifemakers here in the USA have a hardness testing machine or tool ( file, chisel, whack stick). Worldwide, it is probably less than .01%.

People made knives for 1000 years without hardness testers, files, or chisels. They tested their blades to see if the hardness was good.

Today, we are lazy and want some machine (or some other person) to tell us if the knife is good. However, merely knowing the hardness isn't going to tell us if a knife is good, or the steel was properly hardened and tempered.

I'm not saying that having a tester isn't good .. it is great ... but it isn't the be-all and end-all of knifemaking.
Click to expand...
Consumers are more knowledgeable due to internet and forums such as this one.They are asking the right questions about heat treating and hardness testing. Competing for their business means having the Right Tools to back up OUR Claims. So am I to tell a customer Hardness testing "isn't the be-all and end-all of knifemaking"??!
 
Busto said:
Consumers are more knowledgeable due to internet and forums such as this one.They are asking the right questions about heat treating and hardness testing. Competing for their business means having the Right Tools to back up OUR Claims. So am I to tell a customer Hardness testing "isn't the be-all and end-all of knifemaking"??!
Click to expand...
Hardness is only one part of making a good knife, you could take a piece of 1080 and harden it to exactly 60 and check with a expensive tester to know it’s exactly 60 and then you don’t have the right edge geometry and the blade ends up being far too thick and never cutting well or far too thin and it crumbles the first time someone hits a knot in a piece of wood. Neither of those examples would be a good knife but the hardness would be spot on right? If you are doing practical testing with your blades then you can tell if you have a good knife based on creating precise geometry for the intended tasks without even knowing the exact hardness, simpler methods like the chisels let you see fairly accurately were you are on your temper, I can catch if a blade didn’t harden correctly before going further with it and also for those making brut de forge blades or blades with mill scale left on the flats you won’t get a accurate read on a hardness tester but with chisels you can check the edge and know within a point. In my opinion both a hardness tester and the chisels are accurate ways of testing hardness of a blade and can help with consistency but should be backed up with practical testing.
 
Joshua Fisher said:
Hardness is only one part of making a good knife, you could take a piece of 1080 and harden it to exactly 60 and check with a expensive tester to know it’s exactly 60 and then you don’t have the right edge geometry and the blade ends up being far too thick and never cutting well or far too thin and it crumbles the first time someone hits a knot in a piece of wood. Neither of those examples would be a good knife but the hardness would be spot on right? If you are doing practical testing with your blades then you can tell if you have a good knife based on creating precise geometry for the intended tasks without even knowing the exact hardness, simpler methods like the chisels let you see fairly accurately were you are on your temper, I can catch if a blade didn’t harden correctly before going further with it and also for those making brut de forge blades or blades with mill scale left on the flats you won’t get a accurate read on a hardness tester but with chisels you can check the edge and know within a point. In my opinion both a hardness tester and the chisels are accurate ways of testing hardness of a blade and can help with consistency but should be backed up with practical testing.
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I've been at this 20+ years...I'm a journeyman machinist with 40+ years of making chips. I've done all the testing broken all my test sample coupons. I make expensive knives for people that want the best I can produce. I don't use beginner steel and I don't cut corners which may work many makers here, and I understand not all can afford proper test equipment. Do you question Benchmade or Chris Reeve about their products, probably not BUT I get questioned because I don't have their Corporate Names.
 
Stacy E. Apelt - Bladesmith said:
I'm a tool guy, but lets be realistic here. Probably less than 1% of knifemakers here in the USA have a hardness testing machine or tool ( file, chisel, whack stick). Worldwide, it is probably less than .01%.

People made knives for 1000 years without hardness testers, files, or chisels. They tested their blades to see if the hardness was good.

Today, we are lazy and want some machine (or some other person) to tell us if the knife is good. However, merely knowing the hardness isn't going to tell us if a knife is good, or the steel was properly hardened and tempered.

I'm not saying that having a tester isn't good .. it is great ... but it isn't the be-all and end-all of knifemaking.
Click to expand...
After making knives for 10 years and 3 years of looking for a used hardness tester and only finding overpriced incomplete items I gave up.
I retired my files and bought the Grizzly chinese 150. Its dead on accurate and I had many reasons for getting it, laziness is not one.
I had to sell a few knives and I want to give customers an accurate number if they want it. And times change, some users want that info.
it also makes my heat treating a much more fun learning process, you cant experiment accurately with files.
James
 
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