The Value of a Hardness Tester

M

Marc Cooper

Joined
Apr 7, 2019
Messages
60
Hey All

In the last 5 months I've been setting up my new knife shop and testing different methods and techniques for annealing, normalizing, hardening and tempering steel.

I've invested in High-End steel(s), multiple Quench Oils, a Digitally Controlled Kiln and even Liquid Nitrogen Cryo Equipment. Not to mention a new KMG-TX 2x72 Grinder, Milling Machine, Runfa Power Hammer and Hydraulic Forging Press. All to make the best blades possible.

The only issue that arises is that I cannot formally test my steel's Hardness. I can test the edge retention and flexibility through traditional means. I can also test the breaking point and analyze the cracking pattern and grain structure. I just can't test what seems to be my customers number one criteria, which is Hardness.

As most of you know, Testing Hardness on a quality unit like the Grizzly Tester isn't cheap. Especially when you factor-in that it's a 300lb delicate unit that needs to be shipped to Newfoundland, Canada. (One of the most isolated Provinces/States in North America when it comes to shipping large goods.)

As for my testing methodology: I plan on taking 5 blade measurements at different point, dropping any 1 outlier, (via a pre-determined criteria,), and going by the average of the measurements.

This is the question I want to run by everyone here:

Do you think customers will be more likely to purchase a knife if they know the Rockwell Hardness number?

Do you think they would be willing to pay the extra $10 per knife it would take to amortize the machine over the next 4-5 years?
 
You've already spent a lot of money buying equipment to help you make the best quality blades you can. Since you are heat treating in-house and using quality equipment, it would be like driving blind not having the hardness tester. I don't look at it as a customer issue, about buying a knife because they know the Rockell #, I think it is more about you telling you customer with confidence, that I have heat treated and cryo'd this blade and it is at 62Rc. I also and not sure about looking at the amortization of the tester the way you are. You seem serious about your shop equipment, if that is the case, you need the tester.
 
I live in canada and i got one from kbc tools for $1500ish CAD all in. In my opinion totally worth it. I would give them a call. Its just like the grizzly one but already in canada.
 
If you ever want to fine tune a recipe i think its a must. It can also show you if you have a bad batch of steel. You can use it to modify your temper cycles. Hrc isnt everything but its alot. You can have a good number with a poor heat treat but you cant really have a good heat treat with a bad number. I do think testing the exact hardness shows you care. It may not pay for itself in dollars per order but it could be the difference to a customer choosing your knife over someone elses.
 
to answer your main question, you might sell more knives with a certified rc hardness to certain people, but i would not guarantee you would. i never had any problem selling them without one. personally i would rather buy a knife based on performance testing rather than a number. just because your ricasso is at 61 does not mean your tip is. if you can chop through a 2x4 twice and still shave the hair off your leg i would say that shows the heat treat is good. i have done this with 4" blade hunting knives, it takes awhile! for most collectors/users i will say the craftsmanship and stying is the major reason they purchase knives. there is a smaller group who prefer the new modern super steels.
 
john april said:
to answer your main question, you might sell more knives with a certified rc hardness to certain people, but i would not guarantee you would. i never had any problem selling them without one. personally i would rather buy a knife based on performance testing rather than a number. just because your ricasso is at 61 does not mean your tip is. if you can chop through a 2x4 twice and still shave the hair off your leg i would say that shows the heat treat is good. i have done this with 4" blade hunting knives, it takes awhile! for most collectors/users i will say the craftsmanship and stying is the major reason they purchase knives. there is a smaller group who prefer the new modern super steels.
Click to expand...

You are correct in that for many, it’s not important. For my customers it is. I tend to mostly get people looking for higher alloy steels now. They are the people who love Larrin’s articles, and want to know my heat treat process. They like that I can give them guarantees on edge geometry at a certain hardness. Those guarantees come from testing and real world use, not just a Rockwell number though.
 
Yes, a hardness tester is important if you want to know your HT results.

One comment on your proposed testing procedure. You have to test on a spot that is flat on both sides and grind a small area clean of decarb to get a proper result. The tang is the obvious place for this. Testing on five places should not give you different results.
 
Don't take take the customers for granted, just because you can demonstrate nice equipment and Rockwell #'s. I started making blades after five years of making custom handles and sayas (wood cases) for handmade Japanese chef knives. I have sold hundred of handles to professional chefs and home enthusiasts in more than 20 countries in the last seven years....and have a pretty good reputation for quality work. A little over three years ago, I started making my own line of chef knives, obviously coupled with my already successful handles/sayas, I thought it would be an easy sell...I'm making blades and folks really dig my wood work. I admit, I was taken back at how difficult it was to get people, including existing customers, to spend the $$$ on my knives. It isn't about the equipment, though that helps both for you and the customer, but you have to build a reputation as a bladesmith. It is easier for me to charge $200 for a nice Wa handle than it is for a blade. You may need to price lower than you want and get some blades out there and a buzz started about them, and at some point you will naturally decide you can charge more for you knives. It takes hard work, and some smart marketing in today's world, and getting the product out there. Best of luck with it....I am just sharing some of my path.
 
Marc Cooper said:
As most of you know, Testing Hardness on a quality unit like the Grizzly Tester isn't cheap.
Click to expand...

I would not call the grizzly a quality or expensive tester. I would say it’s a passable tool for getting hardness numbers. In my experience the grizzly products are medium duty at best. The price is also really good if you have compared it to other new hardness testers. Not uncommon to see pricing with 5 digits. I have not looked inside one but the lathe, mill, bandsaw and drill press we run at work are piles of shit. And thy are there big industrial items. The only one that I would own is the drill press but I think thy paid around $8k for it. The mill is junk and we have had to fix it a bunch of times.

So that being said I don’t have a very positive opinion on grizzly products. But my willson hardness tester is absolutely fantastic. I would gladly pay what a new grizzly costs for a used Wilson.
 
Owning a Grizzly, I don't think JT is wrong, and in a professional machine or tooling shop, it would be lower end and not my choice. For an individual knife maker, I think it is satisfactory. It does come with test blocks, and it should be tested regularly and calibrated as needed. Most of us aren't making highly technical or aerospace parts, if we can test hardness to a 1-2 point range, it probably suffices for a knife.
 
Quality checks are not value added steps. You've framed your question as though guaranteeing that what you say you're selling is actually what you're selling should cost the customer more. Does that make sense?

The payback with a hardness tester is in your reputation for consistent quality.
 
I had a used ames that I bought off ebay. Bought a couple standards and it tests very well.

I've said this in another thread. If your looking to provide the best possible product than a consistent reading tester is required. Even if it reads 1 or 2 HRC point high or low, doesn't really matter (as long as you aren't advertising those numbers). As long as it is consistent, you can use it to get the best possible heat treat recipe for your setup. Keep in mind that every oven runs different so simply following the published recipes may not be optimizing your numbers. Having a consistent tester will allow you to dial in your recipe for optimal results. Once you obtain your target hardness, you need to snap some knives and beat them up to see how they are really performing and adjust accordingly.

Hardness values are another tool to help you understand what is going on but performance testing is more important to make sure your goals gives the best results.
 
scott kozub said:
I had a used ames that I bought off ebay. Bought a couple standards and it tests very well.

I've said this in another thread. If your looking to provide the best possible product than a consistent reading tester is required. Even if it reads 1 or 2 HRC point high or low, doesn't really matter (as long as you aren't advertising those numbers). As long as it is consistent, you can use it to get the best possible heat treat recipe for your setup. Keep in mind that every oven runs different so simply following the published recipes may not be optimizing your numbers. Having a consistent tester will allow you to dial in your recipe for optimal results. Once you obtain your target hardness, you need to snap some knives and beat them up to see how they are really performing and adjust accordingly.

Hardness values are another tool to help you understand what is going on but performance testing is more important to make sure your goals gives the best results.
Click to expand...

This is true. My tester reads 0.5 to one Rc point high. Consistently. Every time. Two other people have tested my steel, and they get a lower reading. I subtract one off of my results now.
 
scott kozub said:
I had a used ames that I bought off ebay. Bought a couple standards and it tests very well.

I've said this in another thread. If your looking to provide the best possible product than a consistent reading tester is required. Even if it reads 1 or 2 HRC point high or low, doesn't really matter (as long as you aren't advertising those numbers). As long as it is consistent, you can use it to get the best possible heat treat recipe for your setup. Keep in mind that every oven runs different so simply following the published recipes may not be optimizing your numbers. Having a consistent tester will allow you to dial in your recipe for optimal results. Once you obtain your target hardness, you need to snap some knives and beat them up to see how they are really performing and adjust accordingly.

Hardness values are another tool to help you understand what is going on but performance testing is more important to make sure your goals gives the best results.
Click to expand...

I agree with this. I have worked my way up from no tester through 3 testers now and i am so glad I did. one thing i have noticed is if your after consistency then your hardness tester MUST apply the 150kg load at a consistent speed. My wilson has dash pot that controls that. the standard is 4-5sec and i found if your over or under this you can and most likely will get a different number. I'm not quite sure how the grizzly works so i cant say it has this or not. but one thing that stands out as a minor warning to me is having to calibrate it. Hardness testers should not need to be constantly checked and adjusted. My rockwell spring powered version did but that's understandable because its powered by a spring. A dead weight tester should be set, X weight on a 120deg diamond point and it reads the difference in depth from the 10kg preload to the 150kg major load.

When I first got my wilson it did not have weights. I went through it and cleaned everything and built a weight. My research said 25:1 ratio for weights so 150kg is 6,000 grams. I made a 6,000 gram hanging weight out of bronze. I made it a tad light around 5,900g so i could bump it up with a secondary weight. Well it was exactly 2rc low consistently. Im scratching my head thinking something else was wrong and went through everything agian. everything looked good. Then i came across a few posts on another forum where someone had to build weights. people said the extra weights where 25:1 but the main weight and hanger where less as thats whats adjusted at the factory to get it reading properly. So the 40kg and 50kg weight are indeed 25:1 but the 60kg was actually around 1800g. So i went back to the shop and cut 500g off the base of my weight which is alot of material, 500g is 1.1 POUNDS. I came back in and installed the weight and hot damn it was perfect. I have a real nice test block from wilson that's 60.5 +- .5. So what im getting at is it took being off by over a pound of weight to drop the hardness 2rc. These machines are simple and should be 100% repeatable.
 
You must log in or register to reply here.
Back
Top