Hardness tester question

leifjl

leifjl

Joined
Nov 27, 2011
Messages
789
I'm looking to buy a used, but not abused, hardness tester, so I'm on that auction site for a while, and find some that look promising but the shipping is a killer.
Then I figure to look for a portable unit, thinking that portable = less weight = less shipping.

But now I'm wondering about the accuracy of these portable units.

Are there portable hardness testers that are actually accurate enough?

I've just started reading up on all these different testers and any real life input would truly help.

Thanks,
Leif
 
If----- the tester comes with accurite test blocks and consistently reads the hardness
of them you should be good to go. I personally could'nt stand the guesswork and splurged
for a big one. And never looked back.
Ken.
 
I have a small Ames type handheld tester. It will give me consistent results that I have confirmed with a full size tester. I also check it with a test block often, but, think I will make a couple test pieces that are close to normal blade thickness and hardness's (maybe 3 pieces that are 1 1/2"x 8" and 3/32" thick and around 65, 61 and 58) and have them confirmed with a full size tester. My use has shown me that you need to be careful about how you place and hold the unit on the piece for testing as well as making sure you are on a flat surface with parallel sides. But, much of this applies to full size units to some extent as well. If I found the right deal I would rather have a good full size unit.

If you get a small unit make sure it comes with a diamond perpetrator as it is expensive on its own. I can't remember what I paid for mine on Ebay, (under $300) but they are precision equipment and sell for around $2300 new.
 
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I personally would rather have a full size tester. I just bought an old Wilson for $250 with a 7 hour round trip. It was rough and took a full day to get it cleaned up and working, but it is very accurate. There are deals on ebay and one I saw recently with free shipping, looked like a good machine. Anything under $1000 to your door is a good deal for the old US made testers. Be careful though, the first one I bought a year ago was a Superficial tester and didn't test in C scale. You do not want one of those! Also make sure the ones you are looking at have weights 150kg. Most on the bay have no weights, but some do. The Seki Japan ones are also Very good testers!
 
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Speaking of testers, I just came across an old Wilson for $150 but it is 4.5 hours from me and the seller says that it kinda works but not calibrated. The price is good but it's hard to drive such a long ways just to find that it doesn't work.
 
jawilder said:
Speaking of testers, I just came across an old Wilson for $150 but it is 4.5 hours from me and the seller says that it kinda works but not calibrated. The price is good but it's hard to drive such a long ways just to find that it doesn't work.
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I drove 3.5 hours one way and the thing did not work and paid more. We had to blow the dirt dobber nests out of it! If you need/want one, go get it! They are simple machines, easy to work on and adjust. Just make sure it will measure in C scale and has the right weights.
 
SteelSlaver
Yeah, those are the same ones I was looking at. I did figure to verify the reading by using a calibrated full size unit also. I'll make sure about the diamond penetrator. Thanks.

DH3
I noticed quite a bit of the ones I was looking at were described as superficial testers. I guess I will steer clear of those.

Thanks for the replies guys,
Leif
 
leifjl said:
DH3
I noticed quite a bit of the ones I was looking at were described as superficial testers. I guess I will steer clear of those.

Thanks for the replies guys,
Leif
Click to expand...

The superficial testers measure in N scale and are designed for very thin and case harden material. No good for what we do.
 
I bought another Rc tester yesterday. I wasn't goin to do it, but the guy was asking $450 and said he'd take $50. :D
 
I have tested many knives on rockwell testers and not all blade profiles can be tested accurately. Convex blades don't really give an accurate reading because they will wobble under the preloading and main loading of the test, nor do blades that don't have a perfectly flat grind, even the tiniest bit of blade flex or movement will render the test useless. I have found that testing the spine is usually the best bet, closer to the edge can be achived but the grinds on the knife have to be perfectly flat.
 
they really are pretty simple machines and WELL worth the money. I bought a new one and think it's one of the best investments I've made. My tester is less finicky than rjacobsen's about angles (it does have to be pretty flat, but not perfectly and I don't get rocking on convex blades unless I'm doing it in a strange location), but you do have to follow their guidelines on only testing polished surfaces. 36 or 60 grit scratches make it easier for the indenter to indent the miniscule depth it's penetrating and will underestimate your hardness by a few points. Also watch out for decarb on your knives after heat treat as that will throw you off! If the blade has any warp whatsoever make sure that the bow faces up as any bridging or flexing of the steel will mess with it as well.

~Luke
 
Its also a good idea to get a few different types and sizes of anvils for the machine, (anvils are the plates you set the test subject on). The small cylinder types work great for testing knives as it concentrates the test to a very small area on the blade and reduces blade flexing greatly. Your tips were great bloodroot! Btw love that little kiridashi on your web gallery.
 
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