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Thread: Bench grinders and direction of rotation

  1. #1

    Bench grinders and direction of rotation

    I may be missing something(probably my mind!) but all the bench grinders I have seen rotate in a CCW rotation. But I see all kinds of "wheels" advertised for sharpening and honing wood chisels and carving knives.

    It seems to me that if you tried to sharpen a knife or chisel with that wheel rotating toward you the tool would just "dig in" and maybe sling it away from you or into your stomach or an eye. I understand that this wouldn't matter if you used a stone made for grinding and fabricating metal parts, although I know from experience they will catch sometimes also.

    Is this a problem when sharpening carving tools or is it just something you have to master like turning a hunk of wood on a lath? I don't think I could ever "master" honing a carving knife on one of those layered leather wheels with that sucker rotating toward me!

  2. #2
    Join Date
    Feb 2008
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    E TN, near Knoxville
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    Yikes, I wouldn't want to hone with a soft wheel moving towards me either! I have both bench grinders and a Tormek slow-speed sharpener. The bench grinders turn the usual direction but the Tormek turns the opposite direction, with the wheel moving away from the edge from the front. The sharpening stone on the Tormek can be used with the wheel rotating either away or towards you.

    BTW, Tormek says there is no "front" to the machine and it is designed to be used from both sides for sharpening. You are supposed to turn the whole thing around (and move the tool rest) to use it with the wheel rotating towards you.

    Tormek_positions.jpg

    The problem for me is the tool rest/support mount for the "towards" direction is on the top of the machine, too high to be comfortable with the Tormek on my sharpening work table. (And I can't see what I'm doing.) I never turn it around but always use it in the "away" direction for both sharpening and honing. The Tormek manual warns that "Honing must always be done with the wheel running away from the edge."

    If using a bench grinder for honing with a soft wheel seems it would have to be modified to turn the other way, work from the back, or hold the tool below the center line so the sharp edge is trailing trailing. That's the way I use a polishing wheel on a bench grinder (with no tool rest.) But it seems to me a honing wheel would turn too fast.

    Tormek_CBN.jpg

    Some people hone on a wheel mounted on a lathe that will run in reverse.

    All that said I mostly hone turning tools and chisels by hand with polishing/honing compound rubbed into a roughened MDF surface. I resaw a piece of 3/4" MDF on the bandsaw to make the roughened surface. My chip carving knives are stropped lightly on hard leather glued to a board with abrasive compound added.

    JKJ

    Quote Originally Posted by paul handley View Post
    I may be missing something(probably my mind!) but all the bench grinders I have seen rotate in a CCW rotation. But I see all kinds of "wheels" advertised for sharpening and honing wood chisels and carving knives.

    It seems to me that if you tried to sharpen a knife or chisel with that wheel rotating toward you the tool would just "dig in" and maybe sling it away from you or into your stomach or an eye. I understand that this wouldn't matter if you used a stone made for grinding and fabricating metal parts, although I know from experience they will catch sometimes also.

    Is this a problem when sharpening carving tools or is it just something you have to master like turning a hunk of wood on a lath? I don't think I could ever "master" honing a carving knife on one of those layered leather wheels with that sucker rotating toward me!

  3. #3
    Join Date
    Sep 2013
    Location
    Wayland, MA
    Posts
    1,423
    Just rotate the buffer/grinder 180 degrees on your bench and voila! it's turning the other direction for honing.

  4. #4
    What am I missing? The left spins cw and the right spins ccw on the 3 grinders I have. All wheels spin towards the user.

    You have to take care to grind above the center line of the wheel. I found this out the hard way when sharpening my roughing gouge.

  5. #5
    Thanks for the comments! I have an 8" grinder that I bought when I started turning. I don't like to use it even for turning chisels. That sucker sounds like a B-52 taking off! I've been working with wood ever since I was 8 years old and it's always been "safety first!" Can't afford the Tormak but I've got a Wen 4270 on order from Home Depot. I'm sure that it's not the equal of the Tormak but it's got 2 wheels and a switch to change direction. That's what prompted me to choose it. Looking forward to sharpening all my knives an chisels with the acc I ordered with it. Hope the shaft is straight and true or else back it goes to my local Home Depot! That's the advantage of ordering from a local
    chain store. I won't have to ship it back to Amazon!

  6. #6
    I have one grinder with a felt wheel and wire wheel that I turned around on the base so the switch is in front.

    I think the issue is more of safety. With a grinding wheel turning away from you, higher risk of something getting thrown up at you.

  7. #7
    Join Date
    Sep 2013
    Location
    Wayland, MA
    Posts
    1,423
    I thought the question was about honing carving tools on a buffing wheel. If the wheels are rotating towards you you need to work below the centerline where you can't see what's going on. Flipping the machine around to you can work on the top half is much easier and safer.

  8. #8
    You can do a buffer that way because it doesn't have a guard, but grinders have a guard that shields all but a portion of the wheel in front of the operator. I have never owned a buffer because I think those soft buffing wheels would round the corners of the chisel.

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