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Thread: Objectifying edge quality

  1. #61
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    So, the issue w Doug's device is that the same blade point moves along the lenght of the string, not actually slicing, right?

    Having said that, I will say outright that my two methods are the bouncing light maneuver, and the arm hair shave.

    What I like to experience w the arm hair method is-as I move the blade along, the hair-all of it, easily pops off w little resistance.

    I have recently started using the finger pad feeling test.

    The paper slice is a good one that lots of folks use, has no risk of trauma....what kind of paper is the hardest to slice? Newspaper? Phone book sheets?
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  2. #62
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    what kind of paper is the hardest to slice? Newspaper? Phone book sheets?
    Damp tissue?

    The different papers would attest to different levels of sharpness.

    Once you get good at cutting through (remember, not a slicing movement) regular 20# bond paper move up to a cash register receipt. (20# pound bond is the weight of most envelopes and office/copier paper.)

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  3. #63
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    All I ask of my sharpened edges, is that they stay that way long enough to complete a project...or two. Some are getting ready for their fifth straight project..

    In-between projects? I use that "downtime" to refresh an edge or two...rarely needing a full sharpening....just a hone or two.

    Could not care less if they can cut a piece of paper...I'm after cutting wood.....and getting a project completed.

  4. #64
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    Now, JTK, that is funny, wet tissue. That is a joke, right?

    Steven, et al point about getting to work is well made.

    Leonard Lee in his book "Sharpening" says further on in Chapter 1, more or less that sharpening includes
    -keenness of edge
    -shape of the edge, which is dependent on:
    -nature of steel
    -intended use of the tool

    All my hand tools are A2, planes and chisels. Having not purchased anything in some time, recently the idea crossed my mind to get some O1 or PMV11, or Hock blades for a trial.

    What kind of situation would O1 or PMV11 outdo A2, where I would notice it?

    My father in law had given me an old Stanley block plane years ago, and I was getting blade ready to loan out. Wow....certainly helps to realize how nice our steel and tools can be these days.
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  5. #65
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    Before my skin got too thin to be comfortable doing it and my vision got worse...... I use to use a variation on JK’s arm shaving test. I would find a single hair on my arm and try to remove it with a single pass of the blade. Usually if you can do that the blade is sharp.

    I believe A2 is a little more “rubbery”, like stainless than 01 or PMV11. Some testers think A2 is harder to get sharp than 01. There are all sorts of 01, but people who use it seem more interested in being able to sharpen fast, less interested in how long the blade stays sharp. People who like PMV11 prefer to spend a little more time sharpening to get an edge that holds up under use longer. I would suggest reading Derek Cohens practical testing of several different steels http://www.inthewoodshop.com/Woodwor...ues/index.html.
    Last edited by Mike Holbrook; 10-25-2017 at 8:40 AM.

  6. #66
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    Frankly I would put time on your planes more than concern yourself about steels. Wear them out regularly and routinely and resharpen them, this process with frustrate you and provide insight far more than listing off pros and cons of steels will.

    Look for the wear bevel, try and find the point at which you need to resharpen in your work...rinse and repeat.
    Bumbling forward into the unknown.

  7. #67
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    What kind of situation would O1 or PMV11 outdo A2, where I would notice it?
    My paring chisels have a bevel of ~20º. A2 tends to chip more at such low angles. My Low Angle Jack Plane, LN #62 has an A2 blade at 25º. It stays sharp longer, but it does tend to chip a bit. It is used mainly for a shooting plane. The end grain tends to be a bit tougher on a blade.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  8. #68
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    Quote Originally Posted by David Ragan View Post
    What kind of situation would O1 or PMV11 outdo A2, where I would notice it?
    My snarky reply is that it's easier to list the situations in which at least one of O1 or PM-V11 wouldn't out-do A2. Here's the list:

    For that matter I can't think of any case where A2 outperforms PM-V11, though there are a couple where O1 does better than either.

    Seriously, when all else (specifically quality/processing) is equal both O1 and PM-V11 have much finer grain structure than A2. This translates to better initial edge quality, particularly with "soft" natural abrasives. It also translates to less tendency to degrade by chipping, and therefore longer life at low edge angles, where A2 is particularly vulnerable to "carbide dropout".

    O1 has relatively low non-Carbon alloy content, so it's abrasion resistance isn't as high as A2. PM-V11 OTOH is even more abrasion-resistant than A2, though in my experience it doesn't hold up as well as O1 at really low edge angles.

    IMO A2 has simply been rendered obsolete by the advent of powdered metallurgy.
    Last edited by Patrick Chase; 10-25-2017 at 12:18 PM.

  9. #69
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    Quote Originally Posted by Mike Holbrook View Post
    I believe A2 is a little more “rubbery”, like stainless than 01 or PMV11.

    PM-V11 has been described by its manufacturer as "a high hardness Type 440C stainless steel". In terms of composition and behavior it's much close to stainless than is A2, though with the important caveat that it as HCS-ish grain structure.

  10. #70
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    Sharpness tester

    Quote Originally Posted by Andrew Pitonyak View Post
    Very cool..... would love to see some pictures of the device. I would love to make one, but, I know that I lack the time.....

    The primary advantage to a tool such as this is that it is repeatable and not as subjective (as in your don't need to learn what sharp feels like on your nail). One disadvantage, of course, is that you are testing at a single point on the blade.... nothing is perfect.
    Andrew,

    Removing the subjectivity is what we like about the edgeonup tester. I've used mine to check knives and turning tools. Before this tester evaluating the edge on my woodturning skew chisels was by the hair on my arm and "wow, that's sharp". The tester is currently on loan to woodturner John Lucas who is evaluating sharpening methods for turning tools. (perhaps a bit different from hand tools due to the high surface speeds and severe forces.) John also is getting SEM photos of the edges and I loaned him one of my laboratory microscopes for optical comparison. I think he plans to write an article for one of the woodturning magazines. John told me last night that according to the tester the sharpest tools in his shop are his chip-carving knives - no big surprise!

    It does check just a single point but from testing at different points a well-sharpened edge usually seems fairly consistent. I've checked different areas on the same blade and the number were close. They test the machines with single-edge razor blades. They use a digital scale that records peak force. It is important to lower the blade with a slow and steady motion for consistency. For knives they use a fulcrum post for more control. Testing a chisel would benefit from clamping the blade to an arm.

    If building a tester, you might consider buying the media (calibrated mono-filament) from EdgeOnUp. Their filament holder would also be nice - it stores a spool of filament in the base and has thumbscrews to hold a section tight. There are pictures on his web site. All you would need then is to provide a suitable scale.

    If you want to see and try the tester perhaps I could meet up with you the next time I go to Columbus to visit my brother, or if you find yourself going through East TN give me a holler. I've got spare holders and filament if you want to borrow something to play with.

    JKJ

  11. Take a piece of paper (I have a lot of stick-its in the shop). PUSH (not slice) the edge into the paper. If it cuts with little effort and their is NO rough edge to the cut what-so-ever, then I consider that sharp. Test all my edges this way. (I do a lot of stropping, not much sharpening on stones. Easier to keep a blade sharp than to get a blade sharp!)

  12. #72
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    Quote Originally Posted by Brian Holcombe View Post
    Frankly I would put time on your planes more than concern yourself about steels. Wear them out regularly and routinely and resharpen them, this process will frustrate you and provide insight far more than listing off pros and cons of steels will. Look for the wear bevel, try and find the point at which you need to resharpen in your work...rinse and repeat.
    AMEN!! The ability to sense the condition of your edge, and when the time has come to resharpen it is an important skill to develop. If you continue to use the blade past that point, the effort required to cut will increase, while at the same time the quality of your work will decrease, and the wear bevel (or roundover) will quickly become wider (duller) such that the time and stone necessary to sharpen away the wear bevel takes longer than it would if you had stopped and resharpened. Stan
    Last edited by Stanley Covington; 11-03-2017 at 11:52 PM.

  13. #73
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    Quote Originally Posted by Stanley Covington View Post
    AMEN!! The ability to sense the condition of your edge, and when the time has come to resharpen it is an important skill to develop. If you continue to use the blade past that point, the effort required to cut will increase, while at the same time the quality of your work will decrease, and the wear bevel (or roundover) will quickly become wider (duller) such that the time and stone necessary to sharpen away the wear bevel takes longer than it would if you had stopped and resharpened. Stan
    So true. When the tool isn't doing as I like I take then iron to my smooth flat river Rock and give it a rub. When it feels right on the stone I'll take a look at it with some light. Looks good put it back to work. If it doesn't work or feel just right repeat.
    Jim

  14. #74
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    Quote Originally Posted by James Pallas View Post
    So true. When the tool isn't doing as I like I take then iron to my smooth flat river Rock and give it a rub. When it feels right on the stone I'll take a look at it with some light. Looks good put it back to work. If it doesn't work or feel just right repeat.
    Jim
    That is verily the one true "neanderthal approach".

  15. #75
    Quote Originally Posted by James Pallas View Post
    So true. When the tool isn't doing as I like I take then iron to my smooth flat river Rock and give it a rub. When it feels right on the stone I'll take a look at it with some light. Looks good put it back to work. If it doesn't work or feel just right repeat.
    Jim
    I have picked up a few likely looking rocks while hiking, flattened them and tried them for sharpening stones. Some have been better than others, but a few have been quite good.

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