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Need motor recommendation for Surface Grinder

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  • Need motor recommendation for Surface Grinder

    I'm thinking about replacing the motor on a used surface grinder and seeking brand recommendations.

    The grinder currently has a GE K163 (1 HP, 3450 rpm, TENV, 3-phase) driven by an Hitachi L100 VFD. It's belt driven.

    The bearings on the motor are probably bad [1] so my options are to replace the bearings or the motor. Is the GE worth repairing or should it be replaced with a Baldor, Leeson or something else?

    [1] With the belts off, the motor makes some noise on startup and a cup of water sitting on the spindle housing has standing waves on the surface. Thanks to Forrest for that cup of water tip.

    Mike Henry near Chicago

  • #2
    Think I've heard that surface grinder motors are balanced and fitted with expensive high-quality bearings .
    all the best.....mark

    [This message has been edited by aboard_epsilon (edited 12-11-2004).]


    • #3

      The idea that grinder motors must be specially balanced is alluded to fairly often on the web but hard info on the subject seems to be hard to find, at least in my searches.

      A few months back, Forrest suggested that an off-the-shelf motor might be acceptable if the assembler had a good day when the motor was built.

      I figure that I'll either replace the bearings on the GE motor or replace the motor itself if GE motors are not well thought of. If a new one is required I'm leaning toward Baldor or Leeson (both around $150). I'd install and try it as received and then look into getting the motor balanced with pulley attached at a local motor service center if that seemed warranted.

      Dreisilker is fairly local to me here in west suburban Chicago - has anybody ever dealt with them?

      Mike Henry near Chicago


      • #4
        If this is a 3Ph motor, there are only 3 parts that move: the rotor, and the bearings. On the motor 'Plate' it may tell you what the bearing numbers are. Failing that, you can dissasemble it, remove the bearings and get new ones. If they are a standard 62 series, they will be under $10 each. If the bearing seats on the shaft or endbells are worn they can be repaired. Why buy something new, when you can spend many hours fixing it.



        • #5

          There's no bearing info on the motor name plate, but it shouldn't be too hard to pull the end caps and check the bearings. At worst, I'll screw that up and have to be a new motor anyway.

          There's a Motion Industries outlet not too far away so finding the bearings shouldn't be too hard.

          I'd rather fix this quickly than spend a lot of time on it as there are a lot of other projects that have the opposite priority.

          Mike Henry near Chicago


          • #6
            I have been rebuilding a Brown & Sharp surface grinder that has the motor directly coupled to the spindle. It is the spindle bearings that are critical - - about $500 to replace the bearings I am told - - nothing was said about the motor bearings so I am not sure about those but since it is a direct coupling it would seem possible that they are special also. However, if your motor drives a belt which drives the spindle then a normnal motor with regular bearings is fine.

            At least this is what I have been told by a couple of machine rebuilding people in our area.


            [This message has been edited by kruszert (edited 12-13-2004).]


            • #7
              Mike. That sounds like a Boyer Schultz motor. There is no direct replacement. I tried for years to get an oof the shelf motor for mine. It would be much simpler to replace the bearings and balance an off the shelf replacement motor.


              • #8
                I am currently looking at a Cincinatti surface grinder to buy it looks small and has quite a small wheel although I daresay it could easily be fitted with different sizes.They sometimes call them surface/key grinders does anyone no of these type it is non automatic but looks nice ane neat in size for my shop. Alistair
                Please excuse my typing as I have a form of parkinsons disease


                • #9
                  I heard somewhere the the electric motors for grinders are balanced electrically (ie:all the magnetic pulses run in perfect order) as well as being balanced normally
                  Precision takes time.


                  • #10
                    Actually, the grinder is a KO Lee S714 and I'm almost positive that the motor is not original as it looks much newer than the grinder which dates to the mid '70s.

                    I have no problem paying for a new motor if that is the best option, but want to make sure I get the right type and/or brand. I'm not all clear on whether a standard motor can be balanced for a grinder or if a special model is needed.

                    I should have called KO Lee to ask them today but got tied up with work - maybe tomorrow. I'll report back if anything useful results.

                    Reggie - The spindle bearings on this grinder may also need replacing. I'd almost be happy if $500 would take care of that. KO Lee wants $1500 for a spindle replacement. Once the motor issue is resolved I'll be able to tell if the spindle is another issue.

                    Mike Henry near Chicago


                    • #11
                      I contacted KO Lee today and they tell me that the GE K163 motor is/was normal stock for this size grinder and that they don't do anything special as far as balancing goes. He suggested that the 2 belts should be tensioned so that they could be pressed in about 1/8".

                      The conversation was short and I got the distinct impression that the tech support guy didn't want to spend any more time with me than was absolutely necessary.
                      Mike Henry near Chicago


                      • #12
                        Hi Mike
                        When I had my B&S #2 surface grinder, it had a 3600 RPM GE motor on it..ran smooth
                        Someone had changed it from flat belt to V belt and that made Vibrations.
                        I bought one of those Poly V belts like they use on compressors and cars..
                        Made my own pulleys (taper lock) so they were balanced, and it was really smooth after that..
                        Just a thought..
                        I don't like V's on a precision machine as they are not balanced.
                        My Best...Rich
                        PS, when it comes time for bearings, you should be able to find Class 9 bearings cheaper than 750 IMHO..
                        If you downgrade to Class 7's then it will be 350 to 500 I think..
                        &'s work fine for home shop type work..If you want to hold tenths, then 9's are the way