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Thread: Unisaw Motor Action

  1. #1

    Unisaw Motor Action

    I recently bought an older (70s) Unisaw. I immediately had to replace the blade shaft since the threads were messed up. Previous owner would add washers as spacers in from the blade because you could not spin the nut all the way to the blade. While i was replacing this, i went ahead and replaced the bearings and the 3 belts. When i run the blade and stop the motor i almost feels like there is a break that stops the blade quickly. I am not sure if this is just the way it is supposed to behave or if i have over tensioned the belt or have done something else wrong. I have attached a video. Let me know if this is normal action. it also sounds and feels like there is excessive vibration during start-up, never mind that ringing after the blade stops
    I recently bought an older (70s) Unisaw. I immediately had to replace the blade shaft since the threads were messed up. Previous owner would add washers as spacers in from the blade because you could not spin the nut all the way to the blade. While i was replacing this, i went ahead and replaced the bearings and the 3 belts. When i run the blade and stop the motor i almost feels like there is a break that stops the blade quickly. I am not sure if this is just the way it is supposed to behave or if i have over tensioned the belt or have done something else wrong. I have attached a video. Let me know if this is normal action. it also sounds and feels like there is excessive vibration during start-up, never mind that ringing after the blade stops


  2. #2
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
    6,029
    Canít see the video. Uniís are pretty straightforward. Unless thereís a brake installed it should take about 5-7 seconds to stop Iíd guess.

  3. #3
    Trying pasting that link into your browser:
    https://youtu.be/JQGOxMBLK3o

  4. #4
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
    6,029
    0-2. ďThe video is private.Ē

  5. #5
    Simple answer: no that is not normal.

  6. #6
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    4,916
    Take off the belts and stop/start the motor by itself to see if it still happens.
    Bill D

  7. #7
    ok, try now and tell me your thoughts:
    https://youtu.be/JQGOxMBLK3o

  8. #8
    Join Date
    Feb 2010
    Location
    Mt Pleasant SC
    Posts
    297
    Still says private.
    unplug it and rotate blade by hand to see what it feels like. Should be smooth.

  9. #9
    Ok public now. I guess I am questioning how freely the blade should rotate. Itís connected by three belts to the motor at some tension greater than zero and should put some resistance on the motor. But is this excessive.

  10. #10
    Its odd that I can still here the motor winding down after the blade stops spinning: hope this is just a glitch with the video?

  11. #11
    Join Date
    Feb 2010
    Location
    Mt Pleasant SC
    Posts
    297
    The arbor plate nearest the belts that the blade goes up against may be rubbing the arbor bracket. Try again with no blade, if it makes noise let it run for 15 seconds then unplug and feel for heat on that blade plate.

  12. #12
    I will take the table off tomorrow, remove the belts, and see how to motor sounds without anything attached. I will also ensure the arbor plate is positioned out far enough not to be rubbing. I think the whining or ringing you hear is a vibration in the blade itself ( super cheap) that continues after the motor has stopped. I am hopeful I have a good saw.

  13. #13
    Join Date
    Feb 2010
    Location
    Mt Pleasant SC
    Posts
    297
    I would do some checking and looking with the blade off before going to all that trouble.

  14. #14
    Join Date
    Mar 2014
    Location
    Houston, TX
    Posts
    286
    I don't think it's supposed to stop that quick.

  15. #15
    Join Date
    Mar 2016
    Location
    Exeter, CA
    Posts
    483
    I have a 220v 3hp unisaw, bought in prob 97. Belts not tight, pretty loose actually compared to most belts on other machines. Have never adjusted them, all seems to work fine, never has ever stopped or slowed down no matter what i cut with it. Guess my only point here is don't go crazy on getting belts really tight. Especially with three belts. Probably takes 10-15 seconds to stop when turned off. This thing has been bullet proof since I bought it. Dead on and no issues whatsoever.... Randy
    Randy Cox
    Lt Colonel, USAF (ret.)

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