Question about Bench Grinder wheels for hollow grinding

Discussion in 'New to Knifemaking' started by Loosvelt, Jun 18, 2011.

  1. Loosvelt

    Loosvelt Active Member


    Quick question. I am trying my hand an knife making. I am focusing on making small fixed blades and folders. I have use a craftsman 2 x 42 and/or files for flat grinds.

    I would like to do some hollow grinds also. I was thinking about using a mandrel (like tracey sells) attach it to a old motor i have with the four pulleys and use 10" bench grinder discs at lower speeds. Would this work? I thought I remember in the $50 knife shop a bench grinder was used? The mandrel setup could be used to disc grinding and buffing too so it is not like am investing much.

  2. Doug Lester

    Doug Lester Well-Known Member

    Yes, I think that that could work, especially if you keep your speeds down. Be patient, hollow grinds are tricky.

  3. ARCustomKnives

    ARCustomKnives Well-Known Member

    I think you're gonna have a hard time getting a good hollow grind with a stone wheel. I'm not saying it's impossible, but you might be better off putting that hard earned money towards a 10" contact wheel from grizzly and building your own belt grinder.
  4. Loosvelt

    Loosvelt Active Member

    This has also crossed my mind. Since I already have 2 x 42 belts maybe I could make a small one with a grizzly wheel and some idlers.
  5. ARCustomKnives

    ARCustomKnives Well-Known Member

    Even if you buy just have a few 2x72 belts to have on hand, you might be money ahead, and the learning curve will be a lot less steep on a rubber contact wheel than a stone wheel. You might even consider converting your 2x42 to a 2x72. I believe there's a how to in the tutorial section.
  6. Loosvelt

    Loosvelt Active Member


    You are correct. I need to stop cutting corners and just go big and get a 2 x 72. I was going to try to save for a KMG, but I think I am going to buy the NWG frame from USAKM and build a mobile grinder for my patio. Making it in parts would allow me to paint it as I go so it resists rust.

    This would also solve my "holy @@@@ my 2 x 42 is fast" problem.

  7. James Terrio

    James Terrio Well-Known Member

    One concern would be how coarse most bench-grinder stones are. How the heck would you get the rough scratches out? I did my first couple flat-ground KSO's on a bench grinder and that was hard enough to clean up by hand, I'd hate to try smoothing out a hollow that coarse.
  8. James Terrio

    James Terrio Well-Known Member

    I've used a "holy-smokes-this-is-fast" 2x42 for an awful lot of knives and frankly I don't see the big deal about the speed. It just requires a light touch. Maybe I'm just used to it, I sure made a lot of goofs on my first dozen feet of steel or so :eek:

    In fact when I get around to building a real grinder I want it able to go faster. When I'm profiling and setting bevels I like to make some sparks fly and get some work done, baby!

    Of course being able to slow it way down for finer grits and handle materials would be a huge plus too, I do understand that part.
  9. dennie

    dennie Active Member

    As others have stated, a stone wheel is capable of making a hollow grind with perseverance and is a cheap way to start, but cheap may be your own worst enemy. A stone wheel suffers from a diminishing diameter with use. Not a big issue from knife to knife, but after rough grinding, you then need to reface the wheel to get square corners for a good plunge, now the diameter is smaller and you basically have to regrind the whole knife to get a proper hollow. The good side is you can develope the skill and control with a stone on junk steel a whole lot cheaper than belts. When you can grind junk steel and think "Gee, this looks good enough I wish I had used good stuff", you can then moved to belts and will be amazed at how easy it is.


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