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Thread: Delta Unisaw - Motor Running/Belt Not Moving - An account of Safety Feature?

  1. #1
    Join Date
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    Delta Unisaw - Motor Running/Belt Not Moving - An account of Safety Feature?

    Hi All

    So my Delta Unisaw X5 has stopped working. The motor sounds as if it is running (albeit not healthy sounding), but the belt and blade do not spin. It began when the on/off switch stopped working; when pressing the On button, it would start for a second, but would not stay on. However I could maintain power, by holding the on switch compressed. As soon as you let go, it would lose power. I had a couple cuts to make, and so I duct taped the On button so it would stay engaged, or ON. Stupid yes, but I have done this before and it actually started working properly afterward.

    And so, the button was taped down, I made a couple cuts, and instead of removing the tape to cut the power, I pressed the off button, while it was still taped on. I don't recall anything happening just then, but ultimately I removed the tape to shut it off. Soon after, I needed to make a couple cuts with the cross-cut sled( not sure if it's related, but the blade was near max height), again I taped it to stay ON, and while I was cutting I heard what sounded like a piece of steel drop into the saw, and possibly a bit of ricocheting. And then soon after, but not immediately, there was some odd sounds coming from the motor, and then finally the blade stopped spinning, and the sounds coming from the motor would persist any time I press the On button again.

    After looking in the saw cabinet, I saw a small piece of steel. It was 1.5'' long, 3/16 x 3/16 wide. A rectangular prism. It does not appear to have a broken end, they are polished. There is a circular imprint on it. Is this a piece from some safety mechanism that was released with I tried to shut it off while the on button was held in ?

    Any tips on what might have happened or how to fix it would be appreciated. Cheers

  2. #2
    Join Date
    Jan 2008
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    That is the key that keeps a pully locked to a shaft. Also blow out your switch.

  3. #3
    Join Date
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    The key could be from the motor shaft or arbor. It'll be pretty obvious once you get the top off and inspect it. The set screw must have come loose on whichever pulley it came from. If it's missing you might find it in the saw cabinet; probably not, however. Just buy another at your local hardware/auto parts store. Put some thread locker on it when you install the new one. You may have to clean up the key slots in the pulley and/or shaft in order to get it back together. Small files and careful work are the order of the day.

    While you have the top off inspect everything and do any needed maintenance.

    John

  4. #4
    Quote Originally Posted by John TenEyck View Post
    The key could be from the motor shaft or arbor. It'll be pretty obvious once you get the top off and inspect it. The set screw must have come loose on whichever pulley it came from. If it's missing you might find it in the saw cabinet; probably not, however. Just buy another at your local hardware/auto parts store. Put some thread locker on it when you install the new one. You may have to clean up the key slots in the pulley and/or shaft in order to get it back together. Small files and careful work are the order of the day.

    While you have the top off inspect everything and do any needed maintenance.

    John
    Before you take the top off, get some measurements from miter slot to blade, using a dial indicator, or dial calipers. When you replace top, set it in place using these measurements. If you don't, any jig you may have made won't fit.

  5. #5
    Join Date
    Mar 2003
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    9,539
    On my Unisaw there are shims between the table and the base, and it came that way from the factory. When you're removing the table, look for them, and put them back where they came from.

  6. #6
    Join Date
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    It sounds to me like you should be doing a significant amount of table saw inspection and service before you continue to use that saw. Holding the start button on in order to continue using the saw is a safety hazard. Take the time to fix the problems instead of running that saw into the ground.

    I agree with the likelyhood that the key fell out of one of the pulleys. Search through the sawdust using a magnet and you will very likely find the set screws. Since you didn't maintain the saw, it's quite likely that fitting that key into the key slots in the pulley and shaft is going to take some filing off of burrs and cleaning up of both the shaft and pulley. You may even need to buy a new key, since it sounds like that one is now considerably damaged. When you replace the key and pulley on the shaft, it will need to be aligned with the other pulley. This can usually be done by placing a straight edge to bridge across the same side of both pulleys and then move the loose pulley until the straight edge sits squarely on both flanges of both pulleys. Then you need set screws to lock the pulley into place, and a second pair of set screws on top of the first two to lock the first two in place.

    For the motor running problem, it's most likely dirty electrical contacts in the stop button, but could also be dirty contacts in the aux portion of the motor contactor and motor overload heaters on the sides of the motor contactor. All of these are series connected, like old Christmas Tree lights and all must be making good contact to allow the saw to start and run when you momentarily press the start button. These contacts in the stop button must be together for the saw to continue running and open when you push the stop button, and since they are more frequently used, they will likely fail before the others. A narrow strip of fine emery cloth folded in half can be used to clean these contacts. Place the emery cloth between the contacts and hold the contacts together as you pull the emery cloth out. Repeat this several times for each set of contacts. While you are there, do this same thing to the contacts in the start button too. If you are still having problems, then check and clean the rest of the contacts in the stop circuit.

    Charley

  7. #7
    All the above have provided excellent advice; Mr. Lent's is perhaps the most comprehensive - - and I would think gives you the proper roadmap to repair.

    Couple of things I'll add that may seem obvious to some, but bear repeating:
    Unplug the unit before attempting to service it.

    And, arcing occurs every time a contact opens or closes. It can create non-conductive deposits on the contact's surface that prevent it closing, and in some cases, from opening. Visually inspect the electrical contacts - most are plated in silver to reduce arcing and the plating is slowly burned off. It the surface is severely pitted or burned, emory cloth may not do the trick; it might be time to replace the contacts. Replacements are generally available - you need the exact model number of the starter/contactor/relay. If not comfortable with this process, find an electrician.

    I don't have schematics for your saw, but it may not be the Stop Contacts that are at issue, but rather the 'Holding Contacts'. Many circuits use a pair of contacts in the relay to control power sent to the saw, a 3rd contact in the relay 'latches' the electrical power on - and this latch is then broken by the Stop button. It sounds like your electrical issue could be either the Stop or the latch contacts. Again, maybe time for an electrician?

    Good luck and let us know how it progresses.

    Edit: Maybe another X5 owner can chime in ... does this saw have mechanical starter, or magnetic? (If mechanical, my last suggestion may be ...uhm, useless.)
    Last edited by Malcolm McLeod; 02-23-2021 at 9:16 AM.

  8. #8
    Join Date
    Jul 2015
    Location
    SW Ontario
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    Hey Folks, thanks for all the responses. I did try taking the face plate off to blow out the switch, prior to the duct tape band-aid, but to no effect. Although dust is likely the cause, as I had been running a planer near the saw when this happened.

    Is the concensus that the improper use of the On-Switch was not connected to the pin falling out? Just poor maintenance ? I've seen mention of the 'start up kick' or 'jolt' of the motor when it is first turned on, and I think my saw suffers from a bit of that as well, could that have knocked the set screw loose?

    Are there any other factors that could contribute to this problem that I should look for or try to remedy while I have it apart?

  9. #9
    Join Date
    Dec 2006
    Location
    Toronto Ontario
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    10,393
    Quote Originally Posted by John Pond View Post
    Hey Folks, thanks for all the responses. I did try taking the face plate off to blow out the switch, prior to the duct tape band-aid, but to no effect. Although dust is likely the cause, as I had been running a planer near the saw when this happened.

    Is the concensus that the improper use of the On-Switch was not connected to the pin falling out? Just poor maintenance ? I've seen mention of the 'start up kick' or 'jolt' of the motor when it is first turned on, and I think my saw suffers from a bit of that as well, could that have knocked the set screw loose?

    Are there any other factors that could contribute to this problem that I should look for or try to remedy while I have it apart?
    John, I performed maintenance on my cabinet saw twice a year. Your issues sound like they're maintenance ( lack of) related.

    Cleaning, checking, tightening, lubricating.

    Your starter issue sounds like dirt, a failed auxiliary contact or a loose wire............regards, Rod.

  10. #10
    Join Date
    Jul 2015
    Location
    SW Ontario
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    Update: So I removed the top and found what y'all suspected to be the case. However, not only did I find just a single hex fastener in each pulley thread/slot, but that the fasteners were at significantly different depths, so much so that I thought there was two stacked in one of them. Which is to say that one of the fasteners was no where near tight/deep enough to be in contact with the pulley key. Which is why there was only one circular indentation on the pulley key. I hope my feeling of vindication sustains me while I struggle to put everything back together. I guessing you would suggest replacing two hex fasteners in each slot ?

    And so, while I have the top off what maintenance is there to do? I can't find any info on it in the manual, or any much info anywhere. I've lubricated the gears with white lithium spray, as well as the semi circle groove that the 45 tilt moves along. There is a little hole on top of the piece that houses the shaft that spins and moves the blade up and down, is this a lubrication point? Any info, or reference would be appreciated.

    Thanks again, John

  11. #11
    Join Date
    Jul 2015
    Location
    SW Ontario
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    Update:

    So I installed the pulley and tried to line it up with the arbour pulley. In doing so I have to move the motor pulley to be 3/16th off the motor shaft, about a 1/4 away from the motor. I didn't see a way to adjust the position of the arbour pulley.

    will that be a problem?

    Thanks for the help. John

  12. #12
    Join Date
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    The pulley should not extend past the end of the motor shaft.

    Do you think you could post a picture?
    Confidence: The feeling you experience before you fully understand the situation

  13. #13
    Join Date
    Jul 2015
    Location
    SW Ontario
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    Hey Jerry, thanks for replying.

    I could see no way of easily adjusting the location of the arbor pulley, and so I have already put the top back on. And definitely began to worry when I saw your response. But after a bit of forum research I was able to find a thread on here that was pretty close to my situation. I am guessing his saw was probably an older model than mine, but I am hoping the advice he got from Delta would still apply.
    esse Messick
    [OP]Member


    Join DateApr 2006Posts13


    Mac,
    Its the original motor. I called Delta, who were very helpful, and they said you never want to move the arbor adjuster-just the motor pulley. Apparently, it's ok if I have the end of the motor pulley hanging out 3/8" or so from the end of the shaft-they recommend a bit of loctite on the shaft.





    The quote/tagline in your Avatar definitely rang true for me a couple times during this rebuild. I'll have to remember that one.

    A different question I have is about belt tension. The manual says your looking for 1/4 deflection with light finger pressure. It's easier to deflect the belt if your are pushing in towards the pulley, than away from the pulley. I currently have it set up so that I can push it in. And the blade does not spin nearly as freely when you rotate by hand, if I remember correctly (when the motor is off). This could also be because I may not have replaced the belts in the exact orientation that they were on, ie, the natural shape of the belt when you pull it off. Because it spins more freely at different points in it's rotation. I replaced the belts in the same order, but not orientation. I guess I probably could have done more research.

    Does there seem to be a problem in any of what I've described? Any tips on belt tension would be helpful.

    Thanks, John

  14. #14
    Join Date
    May 2008
    Location
    Peshtigo,WI
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    984
    If you have standard v belts and not a link belt they don't care which direction they turn. Your blade won't turn as freely with the belts on because you're turning the motor and the arbor, and having belts on causes friction.

    Check the belt tension by pushing on the belt at the midpoint between the pulleys. Tension isn't checked by pulling out on the belt.

    Be sure the belts don't have any cracks, splits, or pieces missing. If you're unsure of how old the belts are you could replace them and the cost shouldn't be much. Just be aware if you put new belts on they will stretch and have to be retensioned at some point.
    Confidence: The feeling you experience before you fully understand the situation

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