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Thread: Hollow grind chisel without a bench grinder?

  1. #1
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    Hollow grind chisel without a bench grinder?

    I've been putting off sharpening my chisels because I'm too lazy to bust out the sharpening guide (a cheapo version that I never really liked very much) and I'm never satisfied with my freehand honing. I've seen people talk about hollowing out the primary bevel of a chisel using a bench grinder, which makes freehand honing easier, so I'd like to try that. Unfortunately, I don't have a bench grinder. In principal it seems like you could get the same effect using just a round file (or a dremel tool, which I have). Any reason this wouldn't work?

  2. #2
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    Good morning Tim and welcome to the Creek. Your profile doesn't indicate a location. You may live near another member who would be willing to let you give a try to hollow grinding on their grinder. My grinder happens to be a hand crank model. Most of the time I work a flat bevel by hand.

    If a round file can put a hollow grind on your chisels, then your chisels are a bit soft.

    A dremel tool might work. Be careful about over heating the edge.

    What kind of stones are you using?

    If you "cheapo version" of a sharpening guide is what's know as an eclipse stile guide, it may just need a little tune-up.

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

  3. #3
    Quote Originally Posted by Tim Jacobs View Post
    I've been putting off sharpening my chisels because I'm too lazy to bust out the sharpening guide (a cheapo version that I never really liked very much) and I'm never satisfied with my freehand honing. I've seen people talk about hollowing out the primary bevel of a chisel using a bench grinder, which makes freehand honing easier, so I'd like to try that. Unfortunately, I don't have a bench grinder. In principal it seems like you could get the same effect using just a round file (or a dremel tool, which I have). Any reason this wouldn't work?


    I will be interested to see what the experts say. I would think a round file would give you way too much concavity and leave the edge too thin. Same with Dremel. You might try 80 grit sand paper wrapped around a large wooden dowel. I have no idea how hard that would be to make it work, but it seems like it would give you a better chisel contour. Just a thought.

  4. #4
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    As others have said a file won't cut hardened tool steel (the upper limit for most files is around Rc 52, while good chisels are up around Rc 60 or a bit higher), and dremel bits are too small in diameter. You want to minimize the amount by which the bevel angle changes from top->bottom, and in particular you want to avoid having a super-thin edge.

    Why do you want a hollow grind to begin with? Most people regard that as a necessary evil when using a bench grinder, not an end unto itself.

  5. #5
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    The hollow grind does facilitate freehand honing since you feel the bevel lift off the honing stone more clearly than if it were flat. I like this approach since it means touch up honing can be done in just a minute--no honing jig to adjust. I use a 6" grinder, but might prefer an 8" to end up with a smaller hollow. I do use a jig to help assure the grind is square and at a consistent angle. Grinders are awful useful around the shop anyway.

  6. #6
    A hollow grind without a grinder is a bit of a problem. Dremel's tend to heat up the steel very quickly!

    You might want to look into the method from Paul Seller's. He uses a convex bevel. That is a freehand method without a grinder.

  7. #7
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    Quote Originally Posted by Kees Heiden View Post
    You might want to look into the method from Paul Seller's. He uses a convex bevel. That is a freehand method without a grinder.
    If you use water stones you do not want to try this.

    If you do this with a plane blade and get too convex it might interfere with your relief angle.

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

  8. #8
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    Thanks for all the tips, good to know a file likely won't work. It is indeed a eclipse style honing guide, and I've seen the modifications people have made to them (but haven't actually modified mine). The barrier to setting it up is still what I'm trying to avoid, I'd much rather just keep my strop handy and freehand a few swipes to keep my edge.

    I use diamond plates right now (a DMT duosharp coarse/fine). I also have an 8000 grit water stone that I frequently will use as between my diamond stones and my strop. I'll be sure to look into Paul Seller's method.

  9. #9
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    You could use the end of a stationery belt sander, but this requires a special rest for the chisel. Easier to purchase a grinder.

    Regards from Perth

    Derek

  10. #10
    Tim, I would have different advice depending on where you are in life. If you are 65 years old, have worked in an office or cubicle all your life, and have more money than you know what to do with, I would recommend getting a grinder and a honing jig. Or several. If you are 30 and have other pulls on your resources, I would suggest learning to sharpen full flat bevel, freehand on bench stones.

    Frankly there are many many sharpening situations that do not lend themselves to grinder or jig, so if you can learn freehand skills you are that much ahead of the game. And if you are yet young it is a lot easier to acquire skills; the longer you wait the more difficult it is.

  11. #11
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    It kind of depends on your sharpening stones too. These days there are stones that cut so fast that there is little to no advantage to using a hollow grind. I don't find any difference in being able to feel the bevel on the stone whether it's a hollow grind, or a flat bevel. Now a lot of people claim that there is a difference in feel, but I can't understand that-two points or the whole thing, you can tell when an edge lifts, and what it feels like for it to stay down.

    I rarely need to grind a chisel or plane iron any more. The microbevels gradually got wider on my bevels until they took over the whole bevel, and once they did there was no need to regrind. Unless an edge gets damaged, or a new one needs to be reground, they just get what honing they need, which doesn't have to include grinding.

  12. #12
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    Quote Originally Posted by Jim Koepke View Post
    If you use water stones you do not want to try this.
    More precisely you don't want to use push strokes when grinding a continuous convex bevel on a waterstone. Pull strokes should be OK though.

  13. #13
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    I use a hollow grind, but, I think that Rob Cosman does not.... and he does freehand.

    http://www.robcosman.com/tools_angle_trainer.php

    https://www.youtube.com/watch?v=Rvop_JCfZGI

    Here, he is working with a plane blade and he uses the Charlesworth ruler trick (slight back-bevel on the plane blade). Do not do this with a chisel.
    Last edited by Andrew Pitonyak; 02-01-2016 at 9:51 AM.

  14. #14
    The "hollow grind is easier" thing is a bit of an after the fact justification. Bench grinders are great for rough shaping a bevel, and if you do everything including grinding with a jig you do end up with a chisel that you can touch the toe and heel of your bevel to the stone at the same time. This does not make a tool edge that is somehow better, or in my opinion more convenient to achieve.

    I use the grinder to produce an -approximately- flat bevel. A few swipes on a coarse stone trues that bevel up, then to a fine stone to establish a cutting edge. There is waaaay too much energy expended mikling the sharpening process for entertainment value, in my opinion.

  15. #15
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    Quote Originally Posted by bridger berdel View Post
    There is waaaay too much energy expended mikling the sharpening process for entertainment value, in my opinion.
    +1 on that.

    I have sharpened a few blades during the run of this thread. As that shoe company says, "just do it."
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

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