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Mounting a diamond cup wheel on a Baldor style carbide grinder

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  • Mounting a diamond cup wheel on a Baldor style carbide grinder

    Many of you are probably familiar with Baldor carbide grinder and a few of its Chinese copies. They have a reversible spindle and a cup wheel on each side of the motor and metal tables at each wheel to support the tool to be ground. The wheel has a metal backing and is bolted to the hub with 4 screws. The hub itself is sitting on the cylindrical spindle journal, clamped with a nut and has a keyway in its bore which is engaged with the shaft pin to prevent its rotation. This design prevents the wheel or hub slipping on the shaft due to bi-directional spindle rotation.

    In general the design is OK, but it requires the use of special Baldor-style wheels. The selection of such wheels is not great and they are expensive.
    I've just got one of the Chines made grinders and I am trying to design a different wheel mounting to be able to accept a regular diamond or CBN cup with 1-1/4" bore.
    The grinder has 6204 bearings, so the shaft end diameter can be no bigger than 20 mm.

    Have you guys seen how it is done on the industrial tool and cutter grinders? Do they also have bi-directional rotation of the spindle?
    I have a couple of old 1-1/4" wheel hubs of unknown origin. They have a tapered bore with a steep enough taper, which probably makes them self-releasing. They are attached to the spindle with a nut or a screw. The wheel itself sits on a cylindrical hub journal and is retained by a single nut. So the wheel can be removed together with the hub, which makes the wheel exchange very easy. I am just not sure whether such hub would allow bi-directional rotation. The wheel mounting should be secure and should prevent accidental release of the hardware during motor startup. Otherwise the situation may become very ugly. Please don't ask how I learned that...

    Do you have any better suggestions for me? I would appreciate any help I can get.

  • #2
    Yes the wheel hub type can be used bi directional there is usually a keyed washer that goes on before the nut.


    • #3
      One of my tool and cutter grinders has a taper (to locate and align the wheel and flange assembly) and the other has no taper but the removable and fixed flanges are held together with 4 screws - and the spindles on both machines are reversible.

      My surface grinder is uni-directional and the wheel and flange assembly are held onto the spindle with both a taper and a left-hand (ed) nut.


      • #4
        Hmmm Mikey. Thanks for the info.. I learned today, a good day JR
        My old yahoo group. Bridgeport Mill Group


        • #5
          Is your chinese unit a side grinder like the Baldoer tool grinders, or is it a standard unit you want to convert?

          The biggest problem mounting a side type wheel on a machine made for a standard grinding wheel is taking up the length of the shaft that sticks out. The nut and shaft end gets in the way big-time when using a wheel that is plate-mounted, unless you mount it out with a spacer. And if you do, you get out from under the wheel guard.

          If it is already for a plate wheel, you should be able to drill appropriate holes in the plate for bolting onto the hub.

          If you want to use the hubs, they are, IIRC, around a 3" or 3 1/2" per foot taper, and they are key-washered so the clamping nut that holds the wheel at least theoretically is not going to turn due to rotation. The nut that holds the hub on the shaft should be safe due to the taper-mount.

          Keep eye on ball.
          Hashim Khan


          • #6
            I have a side grinder just like Baldor carbide tool grinder. I wish I could post some pictures, but it looks like I am not allowed to do so on this board.

            Thank you for an excellent suggestion about the keyed washer under the nut, which holds the wheel. My existing hubs have a slot at the OD thread, but no washer and I was wondering what the slot is for. Now I know that.

            The existing hubs have about 3 1/2" per foot taper and only one of them has a keyway in the tapered bore - to engage the shaft key I guess. Is it really necessary or should the taper prevent the hub from rotating on the shaft? The other hub does not have a keyway.

            3 1/2" per foot taper supposed to be self-releasing, but is it really so? What is your experience? If a tool is stuck in the Bridgeport spindle, you can use a hammer to strike a drawbar and free it up. It is not so easy with diamond wheel.

            Buy the way, how do you remove and torque the shaft nut (aside of using an impact wrench)- there is nothing provided to hold the shaft.


            • #7
              Is this what it looks like?




              • #8
                Some have a jackscrew thread for removal.

                As for tightening, stuff on a grinder does not get heavily torqued.... the wheel is snugged, and the taper does not require a lot of torque either. If you tighten the wheel excessively, you push right through the blotters and may crack the wheel.

                Keep eye on ball.
                Hashim Khan


                • #9
                  Originally posted by oldtiffie View Post
                  That's it.


                  • #10
                    Yes, this is it.