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Grinding Jig

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  • Grinding Jig

    I've seen several plans/articles describing various jigs for grinding drill bits and endmills, but don't recall seeing such for grinding straight cutters like planner and jointer knives. Can anyone point me toward such an animal? I have both a 6" bench grinder and a Darex cup wheel grinder to adapt something to.
    NOTE: Even tho I'll be grinding on the surface of those knives, I will NOT be calling this a "Surface Grinder"! No Way Jose! Nosir!

    BTW, anyone contemplating running any Pergo flooring across your wood jointer, be forewarned: it'll eat up the edges of your cutters in short order. (unless maybe you have carbide cutters)

    [This message has been edited by lynnl (edited 02-11-2003).]
    Lynn (Huntsville, AL)

  • #2
    Most of the shop made jigs I've seen for sharpening jointer and planer blades require the use of a surface grinder. Take a look at the variuous ones on Grizzly's site and build one. At the price it may be easier to buy one and do some sharpening on the side for cash
    Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


    • #3
      Lee Valley Tools has a jig for grinding planer knifes using a surface plate and abrasive paper or a grinder jig. Their adjustable bench grinder guide table has a slot that can be used to slide a jig to sharpen longer blades with a bench grinder - worth a look.


      • #4
        I am making a jig to sharpen my 16" planer and 6" jointer blades. I'm using 19 inches of 2.5" angle iron with a line of 8 threaded 5/16 inch clamping holes along one side. One edge (side without holes) will be hinged to a base of a length of flat iron and the other edge will have 2 adjusting bolts to raise to the correct angle. _/\_ This will be fastened to my vertical milling machine to be used with a white cup grinding wheel. It should handle blades up to 18 inches long. It could be made shorter. I hope this is clear enough to make sense.
        A quick way would be to fasten the jointer blades to a piece of wood and slide them under a grinding wheel on a radial arm saw.

        [This message has been edited by Gerryrig (edited 02-12-2003).]


        • #5
          Two quick things about jointers and sharping.
          1. When you want to joint something that will damage the knives move the fence all the way to right and make the cut there. After the damage to knives is done the 6" jointer becomes a 5" jointer until you regrind the knives but it may be that the rest of the knives are dull before you need the full width again.
          2. Grinding the knives is not a precision job. You only have get near the correct bevel and get the cutting straight. it won't matter if the cutting not paralell with opposite edge or if width varies from knife to knife. I grind my jointer blades by clamping a stick onto toolrest of a bench grinder and sliding the blade back and forth by hand.
          Hope this helps,