Sunday, May 14, 2017

Photos of New Toy

I grabbed a paring chisel off the rack and tested it. Off the rack it tested to 330 grams. After sharpening on Spyderco brown and white stones it tested to 210 grams.

See photo:


After stropping on leather with 'green stuff' it tested to 160 grams:


I'm not sure how accurate either test was because I was holding the chisel with my left hand while shooting with the right but the numbers are in line with other tests.

Now the next question is: Is 150ish grams a good number or should I be working to lower it? So far 150 grams is the range I've found on different chisels with different steel, O-1, K-510, White Paper, and using different stones and freehand as well as jigged.

More fun with meaningless numbers to follow.

ken 



12 comments:

  1. That is an interesting toy. Do you still have your DMT diamond stones? I would like to see the meaningless numbers for those.

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  2. So...you sharpened away half the steel of your new chisel???

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  3. Dan,

    I've been know to do that. It can happen when you have a sharpening jones.

    ken

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  4. Ralph,

    I can fine 'em gathering dust somewhere. What final grit would you like.

    ken

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  5. Ken,

    I've always been curious about how long a very sharp chisel stays sharper. Is it the case that the sharper it is, the faster it degrades? Would it quickly converge on the sharpness of a chisel that wasn't as sharp to begin with?

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  6. Anonymous8:00 AM

    Couldn't this be done with any suitable scale- just make a little block to hold a piece of string?

    Jim B

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  7. Andy,

    Preliminary checking indicates strop vs. no strop has a larger influence than initial sharpness level. But again that is just a couple of checks and could be just noise, I'm not sure I have enough interest do do enough tests to confirm. Mostly because what I've done for the most part confirms my beliefs. I don't want to be confused by facts :-).

    ken

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  8. Jim,

    I expect it would work but.....there that damn but that almost always shows up....A 5 gram resolution is pretty small and the string is calibrated to sever at a specified sharpness and pressure so test to test should give comparable results. Would be hard to do with a non-calibrated string.

    ken

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  9. with a 170 gram loss per sharpening your scale says you have two sharpenings left before the steel and handle are completely gone. Sounds like maybe your measuring technique has some bugs in it??

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  10. I have never seen nor heard of such a machine, interesting....
    An interesting test method, and revelating.
    From my own experiences a strop edge last longer between the inevitable trip back to the sharpening station.
    Cool gadget you got there, where did you found that??

    Bob, the traveller back from spending Mothers day with the grandma and grand peanuts in Ontario...Piling up the Kms fast lately on my car :-)

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  11. Unknown,

    You have a misunderstanding of how the test works. The measurement is of the gram force needed to cut a calibrated string. There is no loss of metal in the test other than that lost during normal sharpening

    ken

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  12. Bob,

    I ran across it online, dangerous being old and unable to sleep. I doubt it will get a lot of use but it confirmed some things I thought I knew but had no way of knowing for sure and there were some surprises as well. The biggest two are there is no practical difference between natural and man made stones nor is there a difference between using a jig and freehand.
    I had always figured a jig would give a slightly sharper edge than freehand but freehand would allow a sharper working edge because of the ease of more frequent sharpening. It ain't true, in most of the A&B tests freehand had slightly lower numbers (lower is better).

    ken

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