The Value of a Hardness Tester

[Natlek]

Why not use portable / rebound tipe of tester ?? Price is affordable ? My friend have three serious tester but in same place he use this hand hold tester.......it is fast and precisely .

 

[scott kozub]

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.

This is really interesting. I would have guessed the adjustment was internal but this method of adjusting the weight sounds very secure. I'd love a bench top unit but it seems overkill for me. My ames can be adjusted/calibrated slightly by rotating the dial so that the arm that pushes down on the gage has a different leverage. The AMES style testers do require practice. As JT noted above you need to be consistent when applying the weight. Your eye level is even more important. The dial indicator is on a different plane from the glass thing you take the reading from. You have to make sure not to raise or lower your eyeline when testing as dropping your head even a cm or two can through off your reading by a couple hrc. Testing standards are key.

I tend to do blades in batches to save on LN and test every blade and it's amazing how consistent they are. Even with my home built oven. The tester help me to realize that I was over tempering my blades at first.

 

[Larrin]

Why not use portable / rebound tipe of tester ?? Price is affordable ? My friend have three serious tester but in same place he use this hand held tester.......it is fast and precisely .

Not all portable testers are rebound testers. The biggest issue with rebound testers is they generally require quite a bit of material mass to be tested.

 

[Natlek]

Not all portable testers are rebound testers. The biggest issue with rebound testers is they generally require quite a bit of material mass to be tested.

Well , I just make a call.............they require lot of mass , far more then biggest knife I didn't know that

 

[Josh Rider]

A hardness tester is something you can find used for very good prices if you keep looking.
Until then you could try to find someone close to you that can test for you.
If you cover shipping I’d be glad to test hardness for you.
I’d say it’s more important testing your edge and geometry, handle ergonomics and fine tuning that first.
Buy a tester later on to really lock down your heat treat protocols.
But hey, if you can afford one now, go for it!

 

[E.Carlson]

I picked up one 150a benchtop for 400 bucks and just got lucky and snagged another newer version off ebay for 200 shipped. If you're patient you can get one on the cheap. Both mine work perfectly.

 

[Marc Cooper]

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.

This is exactly what I wanted to hear and why I wanted a tester. Your last sentence made me go online and order it.