A New Toy

[george wilson]

I wish you'd post a picture. Never heard of a sharpness tester.

[John K Jordan]

I wish you'd post a picture. Never heard of a sharpness tester.

George, there are pictures and more info on the Edge On Up web site: http://www.edgeonup.com/

I was skeptical at first but an hour on the phone with Mike Brubacher answered enough of my questions that I decided to buy one. Tests with razor blades showed it to be quite repeatable. The function of this is somewhat similar to the industry standard CATRA tester ( http://www.catra.org/pages/products/kniveslevel1/st.htm ) but affordable to a hobbyist and probably accurate enough.

I found out about this from Ken schroeder, "Tormak Man" who checks into SMC on occasion and moderates the Tormek forum. I believe it was he who said the Edge On Up testers are starting to be used widely by knifemakers to evaluate sharpness.

JKJ

[bridger berdel]

If I'm understanding you right Ken you're saying that the tester cannot tell the difference between stones. To me that says that either the tester lacks sensitivity in a range that is important to me or that I'm fooling myself believing that I can subjectively tell the difference in edges from different stones.

[ken hatch]

If I'm understanding you right Ken you're saying that the tester cannot tell the difference between stones. To me that says that either the tester lacks sensitivity in a range that is important to me or that I'm fooling myself believing that I can subjectively tell the difference in edges from different stones.

The unit has 5 grams of sensitivity, Results will be within a 10 gram plus or minis range, in other words 140 grams to 150 grams could be the same.

No I do not think you are fooling your self but if the test result are the same for different stones then you may have sensitive fingers, in other words your analog fingers can feel a 10 gram difference. Not bad old chap.

ken

[bridger berdel]

how far apart do the stones need to be for the tester to register a difference? you say it doesn't distinguish between spyderco uf and surgical black ark. I doubt I can pick those out by feel, but what about the difference between say washita and surgical black? I'm sure I can feel that, in the cut if nothing else.

[Graham Haydon]

Ken, you manage to take something I'd normally roll my eyes at and turn it into something interesting and fun. It's a rare talent! I'd love to see the reading from an fine India stone and a light strop.

[ken hatch]

Ken, you manage to take something I'd normally roll my eyes at and turn it into something interesting and fun. It's a rare talent! I'd love to see the reading from an fine India stone and a light strop.

Thanks Graham, that was good for a laugh. I don't have a fine India but I expect the results wouldn't be much different that those from a hard Ark or maybe a Washita.