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Thread: Jet 1642 Motor gone bad

  1. #61
    Join Date
    Apr 2012
    Location
    Great Falls, VA
    Posts
    813
    Jim, interesting update. Be sure to give us another once you get the motor back from the shop. I know overtight belts can cause bearing failure, but a bent motor shaft is a new one to me.

    Do you suppose belt overtightening could be the culprit in some of those other reports of Jet motor failure? The 1642EVS has been around quite awhile and is highly regarded. I've heard of very few problems with it.

  2. #62
    Well, that had occurred to me as well. I never moved the belts into a new position until sometime in the past two years... I can't remember if the motor comes attached to the headstock or not, so I don't know if I initially put it on. If I did, I must not have gotten it too tight that first time.
    But I didn't think I'd gotten it too tight this last time... Apparently I did.
    CarveWright Model C
    Stratos Lathe
    Jet 1014
    Half-a-Brain

  3. #63
    As for the shaft leverage question, the shaft is turned down to 16mm (just over 5/8") for the pulley. And the shaft sticks out approximately 75mm (3 inches) from the face of the motor. So the belt tension does have a good bit of leverage on a fairly small shaft.
    CarveWright Model C
    Stratos Lathe
    Jet 1014
    Half-a-Brain

  4. #64
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298

    Thank you for this info!

    Wow! Great (and happy)followup!

    It was so fortunate you found the right motor guy. You are a real man in my book to even mention this - I suspect many would never admit it and let it drop. Thank you for this info - I'm going to go check the belt tension on my 1642 lathes and the smaller lathes.

    I remember my 1642 manual said to let the weight of the motor supply the belt tension, implying no additional tensioning necessary. What it DIDN'T do was warn against additional tensioning. Maybe Jet would add a note in future manuals if you prompted them, or put a sticker on the inside of the belt door.


    I've heard it is better for engine fan belts to be a bit too loose rather than too tight - just tight enough to not slip. I thought it was to keep the belts from wearing excessively. (Just had a belt disintegrate on my bobcat, bought used, and I confess I've never checked the belt tightness.) I imagine an over-tight fanbelt might damage an alternator or other component. Thank you again for the education.

    This might be good to post in the other forums you mentioned. Maybe many others are overtightening - you might save an untold amount of grief. Perhaps some of the other failures you read about were from the same thing. We all often overdo things - if a little is good then a lot must be better. I once bought several Nova chucks from a guy that had been over-tightened so much the metal in the chuck body had deformed. He must have used a cheater bar on the chuck key!! Took me hours to rework them.

    I may put a note on my two and the 1642 used at our club demos. Might be a good note to put in turning club newsletters as well. I wonder if other lathe models have similar belt tightening requirements.

    I hope the kind motor guy's efforts fix your motor. Maybe send him a gift card for a resturant or something!

    JKJ

  5. #65
    Join Date
    Mar 2015
    Location
    cleveland,tn.
    Posts
    385
    kinda makes me wonder how much extra bowing would be caused when you have 25 lbs of unbalanced wood between the centers spinning?

  6. #66
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298
    David, The wood is not supported by the motor shaft but by the spindle shaft. The spindle is massive (and with heavy duty bearings) compared to the motor. Flexing or movement in the spindle, if any, would be isolated from the motor by the belt.

  7. #67
    Join Date
    Mar 2015
    Location
    cleveland,tn.
    Posts
    385
    yeah your are right I do not know what I was thinking,I guess I was focused on the motor as it being direct drive. duh stupid

  8. #68
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298
    Hey, for a moment I thought the same thing when I heard about the bent shaft - maybe it was a big chunk of wood or a massive catch. Then I remembered how that lathe is made! I should have known, I've got two of them in my shop...

  9. #69
    Well phooey. I put it all back together tonight but it still makes noise under power. The guy at the motor shop said it was only off by .0005" after he trued up the rotor.
    Something is definitely messed up with this thing.
    I'll post a video at some point...
    CarveWright Model C
    Stratos Lathe
    Jet 1014
    Half-a-Brain

  10. #70
    Join Date
    Jan 2009
    Location
    Williamsburg,Va.
    Posts
    12,402
    Asian motors are crappy,just crappy. I had the motor on our 16" x 40" Taiwan made Grizzly lathe short out through the bearings. The museum's electricians said the motor was junk. One problem is the Asian motors do not have the commutator dipped in insulating varnish.

    In your case,the problem is probably that Asian motors(and a lot of other stuff they make),just use poor grades of metal. So,your shaft bent. Their electronics are also always questionable. I had a Jet wet wheel grinder that was brand new quit working after just a few hours of use. When I called the Jet repair facility,I got a long lecture from the head idiot on how proud they are of their products. How can you deal with that kind of stupidity? The guy obviously knew nothing about REAL quality. DEALERS told me that often these Jet grinders do not work straight out of the box!

    Finally,I got them to agree to send me a new $2.75 circuit board. When I took the grinder open,I discovered that the push on connecters were LITERALLY as thin as beer cans. When the assemblers push them on,the connecters crack,and soon stop conducting electricity. So,I soldered the cracked connecter,and the grinder worked again-for a few more hours. Then it quit again. Before I got around to opening the blasted thing again,a friend gave me a Tormek wet wheel grinder. The Jet just sits there,taking up space. I might salvage the wet wheel off of it,but i'm tired of fooling with the stupid thing.

    Years ago I had a Jet metal lathe whose motor stopped working. This was in the 80's. They could not take a VISA card over the phone. The parts guy was a real jerk. Very bad attitude. No help to the customer at all. I made the mistake of sending a check to Seattle from Va.. It took me 19 days to get the $2.00 part that they soaked me $20.00 for. I vowed I'd NEVER buy a Jet again. Then,I made the mistake of buying that grinder. Truly,I AM DONE with them!!!!!!!!
    Last edited by george wilson; 05-24-2015 at 5:23 PM.

  11. #71
    Join Date
    Mar 2015
    Location
    cleveland,tn.
    Posts
    385
    do you remember how far the shaft was out before being trued?

  12. #72
    Never did check it. The rotor was scraping the coil laminations (only under power) and obviously (to the eye) the runout on the pulley shaft was out of acceptable range.. When I put the whole shaft between centers (after disassembly) the runout was less (by eye), but still unacceptable. When I put the case end caps on the bearings (without the case) and clamped the end housings in my workmate and spun the thing by hand it was still unacceptable. I can't remember if it was less or more and can't verify that because I measured nothing.
    I suspect it's right back to where I was when I started out...

    I'll try to post the video sometime today...
    CarveWright Model C
    Stratos Lathe
    Jet 1014
    Half-a-Brain

  13. #73
    Here's a video I shot of the pulleys after first putting the motor back on. The only tension on the pulley is what the weight of the motor put on it. I first ran it up with the EVS, and you can hear the "scrape, scrape" noise at very low speed. It tends to diminish as the speed goes up. At the end of the video you can see I turned it by hand, and there's no more "scrape" noise. After I made the video, I removed the belt from the pulley and removed the chuck (which you can hear making a small "clack, clack" noise) and ran the thing under power- still makes the same "scrape, scrape" noise.

    I suppose I could make a video (without belts on) that backs off of the opening so you can hear and see where the noise is coming from.

    CarveWright Model C
    Stratos Lathe
    Jet 1014
    Half-a-Brain

  14. #74
    Join Date
    Jan 2012
    Location
    Roseville,Ca
    Posts
    455
    Jim,
    When I attempted to watch the video, I got a message " This video is private"

  15. #75
    Try it now. I turned off the privacy setting.
    CarveWright Model C
    Stratos Lathe
    Jet 1014
    Half-a-Brain

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