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Thread: A2 iron micro chipping

  1. #1
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    A2 iron micro chipping

    I have a LN bevel up jack that I use for shooting and the blade is currently hollow ground at 25degrees. I sharpen freehand on diamond stones and finish on a strop with green compound. Recently I started getting scratches in the end grain that I assume indicates micro chipping. I have researched an old thread on here and I have seen David Weaver's discussions and video on A2 steel and why it should be ground at a higher angle to prevent chipping. Question is: How can I use this blade as a low angle when the remedy seems to be running a higher angle that will result in a less than ideal end grain angle of attack?

  2. #2
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    Is it a new blade? They tend to be more chippy at the edge. If that the case you can either wait or just grind the edge back a little to get to the 'good' steel. My LV LA jack is also A2 and it didn't hold well at 25 when new but its does pretty well now. Also, don't worry too much about the angle. A 30 degree bevel puts you at 42 degrees which is plenty low enough to do well on end grain. Honestly it is my opinion, that while a low angle certainly helps on end grain, the NEED for it tends to be over stated. Standard 45 degree Baily style planes handle end grain just fine. I'm not saying it makes no difference. I have several planes that I keep at low angle exclusively for gain use, but I don't think you'd be let down by a 42 degree included angle. A blade that stays sharp is far more important than a low angle.
    Last edited by Chris Griggs; 09-18-2015 at 9:56 AM.
    Woodworking is terrific for keeping in shape, but it's also a deadly serious killing system...

  3. #3
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    Thanks Chris,
    I should also mention that my number 4 (with an A2 blade bevel down) Also has a 25 degree bevel and it works fabulous on end grain. In fact, while attempting to get rid of these "lines" that the bevel up plane is leaving, I am using my #4 to re-establish a fresh layer of end grain. So your point is well taken on the angle being less important than sharp. The #4 literally glides over end grain, almost surprises me that it is cutting at times. The bevel up has always seemed to fight me and never plane with ease like that. Do you think it could be a metallurgy issue? I have ground it back at least 1/16th or so in an attempt to unearth better metal.
    Last edited by Mike Cherry; 09-18-2015 at 8:55 AM.

  4. #4
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    I don't know a lot about metallurgy. I guess if it were me I would try it at 30 degrees and maybe grind back another 16th. Or at a minimum grind to a fresh big burr just to make sure there weren't old chips that I just hadn't fully honed out. I would also check that back of the blade. Sometimes you can hit a bit of dirty wood that will scratch the back of the blade and create scratches in the wood that look like microchips.

    If you take it up to 30 and grind a little more off and still have chipping problems then I might start to worry that it a metallurgy issue. I did get a bad blade from LV once so it is possible, but in that case the edge was rolling and it was pretty obvious that it wasn't properly hardened. What your seeing could also just be individual variation between blades, but still be within spec. Its hard to say. Some blades are just a little harder/softer better/worse than others.

    Worst case scenario if you really start to suspect a metallurgy issue you can send it to them and they'll probably test it, but at this point I wouldn't be confident that its out of spec. While A2 can hold and edge at 25 degree, most people will tell you its not ideal.
    Woodworking is terrific for keeping in shape, but it's also a deadly serious killing system...

  5. #5
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    Hi Mike

    Chris' point of grinding back a little, if the blade is new, is appropriate in my opinion. Otherwise I have not experienced any problems with either LN or LV bevel up A2 blades at 25 degrees.

    Keep in mind that the bed angles here are 12 degrees. The amount of stress on the edge of the blade seems to be so much less here than when the bed angle is a bevel down 45 degrees. In the case of the latter, it is advisable to have a 30 (even 35 degree) degree bevel. Anything under this, in my experience, does not last particularly long (for that matter, few steels work well with bevels less than 30 degrees when the bed is 45 degrees). I would say that the higher the bed angle, the greater the stresses placed on the edge of the blade.

    The point is, with a BU plane and its 12 degree bed, an A2 blade at 25 degrees should long the pace. All mine do (I used a LV LA Jack as a shooter for some years).

    Regards from Perth

    Derek

  6. #6
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    Chris I think I will take your advice and make sure I have a nice big burr before I re grind a different angle. I will look at the back a little closer as well.

    Derek, I appreciate the advice. In what capacity do you utilize a bevel up 25 degree blade, in your actual woodworking? I ask because I seem to remember you having a shooting plane or two that you use. I know that you work relatively difficult woods.

    I did notice a hint of a burr after using the iron on a couple of occasions. Is this "folding over?"

  7. #7
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    I would at least bounce this off LN. I now run a PM-V11 in my Lv LA Jack for shooting. The A2 that came in it and another IBC that I picked up all get used and seem to perform well.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  8. #8
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    Quote Originally Posted by Mike Cherry View Post
    ...Derek, I appreciate the advice. In what capacity do you utilize a bevel up 25 degree blade, in your actual woodworking? I ask because I seem to remember you having a shooting plane or two that you use. I know that you work relatively difficult woods ...
    Hi Mike

    When I reviewed the LV Shooting Plane (which has a 12 degree bed in a BU config), it was possible to draw conclusions as I compared it with a LN Shooting Plane (which has a 45 degree bed in a BD config). The article is here: http://www.inthewoodshop.com/ToolRev...tingPlane.html

    The results clearly demonstrated the superiority of A2 at 25 degrees when used in a BU plane.

    As to current BU users at 25 degrees, there are all my block planes, as well as LA Jacks.

    Regards from Perth

    Derek

  9. #9
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    So I did a quick regrind on the CBN wheel to 35 degrees just to satisfy my curiosity and below are the results.

    This is the results at 25 degrees
    image.jpg

    This is after re grinding to 35 degrees
    image.jpg
    quick video shooting end grain with results:
    https://youtu.be/FoDur90NJK9Y
    Last edited by Mike Cherry; 09-18-2015 at 11:43 AM.

  10. #10
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    Now I am pleased with the results, but I'm still searching for answers. The plane is designed to work on a 25 degree primary bevel, much like a block plane. Is this one of those moments in my personal woodworking journey where I realize I don't need this tool? I am sitting at 47 degrees after you account for the bed angle. I can get just as good results with a bevel down plane. What am I missing here?

  11. #11
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    FWIW I have the same LN plane. My recollection is my blade bevel is at 25º. It did have a chipping problem at first, but that seems to be history after so many times sharpening.

    Your first picture looks a lot worse than mine ever did. Mostly mine would get one or two chips at most.

    My experience with getting the blade as sharp as I can and taking as light a cut to make a shaving with the bevel at 25º works fine for me. Most of the time I am using soft woods so that is likely a big variable.

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

  12. #12
    I guess the next question is whether the improved performance is because of the angle change or because you got past the fussy steel that may be at the leading edge of some new blades. Try using it for a while like you have it and then after you've sharpened it a few more times, try backing off on the angle again to see how things go. I've had several new irons that were a bit grumpy until they'd been sharpened a few times then they did just fine.

  13. #13
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    Yeah that 25 degree shot definitely is not how A2 should look at 25 degrees in a low angle plane. As Barney says, grind back down to that at some point. If that's happening after a stroke or two your blade is either too brittle or its too soft and the edge is rolling.
    Woodworking is terrific for keeping in shape, but it's also a deadly serious killing system...

  14. #14
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    What is the diameter of the wheel that you are using to grind that HOLLOW GROUND 25º angle on your A2 iron? If the wheel is fairly small,the angle it is grinding at the cutting edge could be considerably less than 25º.

  15. #15
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    I had the same problem with my LN low angle jack. It goes away. I used a micro bevel until it was sharpened a few times, now it doesn't happen anymore.

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