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Thread: Slow grinder bearing replacement

  1. #1
    Join Date
    Apr 2007
    Location
    Durango, CO
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    155

    Slow grinder bearing replacement

    I purchased a no-name 8" slow grinder from Woodcraft about 5 years ago. It sounds like I have a bearing going out, and am wondering if anyone else has replaced bearings on a similar grinder. If so did you have any issues with the process? Is it somewhat easy or a nightmare?

    Thanks,
    Greg

  2. #2
    It will probably be easier/cheaper to have it repaired. I did a Google search for "electric motor repair, Durango Co " and found three listings.

  3. #3
    Join Date
    Apr 2007
    Location
    Durango, CO
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    155
    Dwight, for what they charge around here I could buy a new grinder. I had another motor repaired and they charged me 3x what the quote was.

  4. #4
    Join Date
    Jul 2008
    Location
    Atikokan, Rainy River district, Ontario
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    Greg it isnít very hard to change your grinders bearings, or motor bearings, as thatís all it is.

    You do need a good large enough puller and take your time doing this.

    You do one side first and when done with that do the other side, before starting make a scratch from the housing over and onto the end bell, that way you will be able to get the end bell back at the exact same spot as it was.

    Take off the wheel and check there are no rough spots on the shaft or at the shoulder where the washer/flange sat.

    Remove the nuts probably 4 and push or pull the rods back a little than use the puller to remove the end bell, the bearing might stay in the end bell or on the shaft, remove the bearing and go get two new bearings.

    Put the bearing and end bell back on and also the wheel, itís easier now with the other wheel still on tight.

    Then do the other side and youíre all done

    Oh yes, you probably know this already, the nuts for the wheels are RH thread on the RH side of the grinder (RH as you are facing the grinder) and LH thread on the LH side of the grinder.
    Last edited by Leo Van Der Loo; 01-08-2017 at 9:51 PM.


    Have fun and take care

  5. #5
    Join Date
    May 2009
    Location
    Boston
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    It can be done but I'd buy a new one. You can get one for 125.00 with no aggravation.
    Don

  6. #6
    A worthwhile reason to replace bearings on "older" grinders and such is being older the machine likely is better quality than a new version. Whether the OP's 5 year old grinder from Woodcraft fits in the older-is-better category is open to question.

    Awhile back I ran across an old Craftsman grinder with a bad switch. It's the style Craftsman has sold for years with the flat front and back motor housing rather than the typical round motor housing. Replaced the switch and general fix up including bearings. In the process I noted this grinder is all cast iron rather than die cast alloy and stamped wheel covers like the newer models. It's close to twice the weight of the visually identical newer model and runs so quiet and vibration free it was worth the effort to repair. My guess is this grinder could be from the 1950's.

    Replacing bearings is about as simple as Leo described, sometimes even easier, sometimes a bit more trouble.

    BTW: My all time favorite place to buy bearings is Motion Industries. They're all over the country and mail order. Very, very seldom will you find identical bearings for less anywhere else.

  7. #7
    Join Date
    Apr 2007
    Location
    Durango, CO
    Posts
    155
    Thanks all. I didn't think it would be all that difficult to replace the bearings as I've done this in a few saws. I agree the older tools are usually worth repairing. I rarely see older slow speed grinders for sale. Does it hurt to sharpen at 3400 rpm?

  8. #8
    Quote Originally Posted by Greg McClurg View Post
    Thanks all. I didn't think it would be all that difficult to replace the bearings as I've done this in a few saws. I agree the older tools are usually worth repairing. I rarely see older slow speed grinders for sale. Does it hurt to sharpen at 3400 rpm?

    I have a surface grinder that using 7" diameter wheels and a tool and cutter grinder that mostly uses smaller diameter wheels. Both machines are direct drive, nominally 3600 rpm. Both machines have diamond, CBN and aluminum oxide composite wheels. No plated wheels. As long as the wheels are kept clean and dressed speed has never been a problem grinding high speed steel or carbide tooling.

  9. #9
    Join Date
    Jul 2008
    Location
    Atikokan, Rainy River district, Ontario
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    Quote Originally Posted by Doug Rasmussen View Post
    I have a surface grinder that using 7" diameter wheels and a tool and cutter grinder that mostly uses smaller diameter wheels. Both machines are direct drive, nominally 3600 rpm. Both machines have diamond, CBN and aluminum oxide composite wheels. No plated wheels. As long as the wheels are kept clean and dressed speed has never been a problem grinding high speed steel or carbide tooling.
    Agreed Doug, however with speed comes more vibration especially with the cheaper build grinders, motors.

    I compare this to driving a car at 60 miles an hour on a smooth road, and then do the same at 120 MPH, the seemingly smooth running car is not running so smooth anymore, that is every little bit out of balance or unevenness affects this to the power of,

    Of course a sharp wheel at double the speed is able to remove material at double the speed, nice if you are in a hurry and have a soft touch, not so much if you are not and grind away expensive steel unneeded, just IMO 1thumb.gif


    Have fun and take care

  10. #10
    Quote Originally Posted by Leo Van Der Loo View Post
    Agreed Doug, however with speed comes more vibration especially with the cheaper build grinders, motors.

    I compare this to driving a car at 60 miles an hour on a smooth road, and then do the same at 120 MPH, the seemingly smooth running car is not running so smooth anymore, that is every little bit out of balance or unevenness affects this to the power of,

    Of course a sharp wheel at double the speed is able to remove material at double the speed, nice if you are in a hurry and have a soft touch, not so much if you are not and grind away expensive steel unneeded, just IMO 1thumb.gif
    Yeah, agreed Leo. My machines, for their purposes, have precise motors and spindles. Not so in the lower end bench grinders of course.

    I Have no experience with plated wheels and wonder about putting a plated wheel on a high speed grinder. The wheels discussed here seem to be on the cheap side so may not run true and vibration free at 3600 rpm.

  11. #11
    Join Date
    Jan 2006
    Location
    Chicagoland
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    2,403
    I'm far from an expert but I changed bearings on a 1950 Uni with "bullet" motor and on a PM lathe motor. Just needed to get a set of bearing pullers from HF, right size pipe/cylinder to drive on the new bearings, and suggest you get bearings from Accurate Bearing.

    That being said, if it's time to upgrade to CBN, Woodturners Wonders has a good price on the Rikon 1HP slow speed grinder with or without wheels.

    Mike

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