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Thread: Delta Unisaw Starter Switch and Box

  1. #1

    Delta Unisaw Starter Switch and Box

    I bought an older Rockwell Unisaw. The starter switch was not working well (sticking in the on position). I purchased what i thought was a direct replacement as shown in the photos and it turned out to be deeper than the one it came with. It does not fit into the box attached to the saw. So I am looking for the full solution; a switch/box and how to attached it to the cabinet or table.
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  2. #2
    Join Date
    Feb 2010
    Location
    Mt Pleasant SC
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    682
    Does it not have a box from the same company available? Then take the new switch to a big box store and find a metal surface mount box that fits it. If you find one too shallow they have box extender rings too.
    Edit: After reading more posts I realize now that your new switch is for a band saw. You need a table saw magnetic start/stop assembly.
    Last edited by Bruce King; 01-24-2021 at 12:20 AM.

  3. #3
    Join Date
    Dec 2006
    Location
    Porter,TX
    Posts
    1,330
    Seeing that its a round hole that it must have had a surface mounted J-box. One I had the box was recess into the cabinet, if it was me I would look on line or go down to HD and find a box that would work for you. There are several as long as your not trying go back to original. Like Bruce saying you can get a box that is say a 4" x4" that you can put on a single gang extension ring. The box is called 1900 box by elec trade, or you can go with just single gang switch box. Or to have more rm in that box for that switch can go with one of those weather proof box that is made out of cast aluminum,which you can also get an extension ring for it.
    Either way,that is one nice saw
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    Last edited by Carroll Courtney; 01-23-2021 at 6:14 PM.

  4. #4
    That looks like a yucky mechanical switch rather than a nice magnetic starter. Check out Grizzly. You can get a real magnetic switch there for around $100; definitely worth it. Just match your voltage and horsepower.

  5. #5
    is the only purpose of a magnetic switch to prevent the saw from turning back on after a power outage? Meaning can i just simply replace with a normal 220V electrical switch?

  6. #6
    Quote Originally Posted by jeff friedman View Post
    is the only purpose of a magnetic switch to prevent the saw from turning back on after a power outage? Meaning can i just simply replace with a normal 220V electrical switch?
    Sort of. They do prevent the saw from starting after an outage, but they also have an overload sensor to protect the motor, (which is why they are rated by horsepower).

    There is also a bit of a safety aspect, in that it takes less pressure to engage the stop switch on a magnetic switch than a mechanical one, reason being the magnetic switch just needs to interrupt the current going to the relay, whereas a mechanical switch you need push a much heavier set of contacts apart. If I was desperately swatting at a switch to turn a saw off (like if I only had one available or functional arm), I would want it to be a magnetic one.

  7. #7
    Quote Originally Posted by jeff friedman View Post
    is the only purpose of a magnetic switch to prevent the saw from turning back on after a power outage? Meaning can i just simply replace with a normal 220V electrical switch?
    A magnetic switch would be a simple relay. A motor starter is different and serves a few purposes. Thermal overload protection being the primary function. The overloads either melting alloy, called "heaters" or solid state can be purchased or set just above the full load amps (FLA) of the motor. This provides the thermal protection. On three phase motors, the motor will not start on only one phase. It will quietly hum away until it over heats and all the smoke leaks out. A manual motor starter will not open (turn off) if power is lost and reapplied. A magnetic starter will not close in until the "start" circuit is energized. Depending on how the control circuit is wired it will prevent a motor from being accidentally started after a loss of power, this is not always true. An air compressor or air conditioning may automatically start. Magnetic starters also allow for remote and multiple Start/ Stop stations.

    The motor should have some form of thermal protection, either internal or external. If the motor doesn't have thermal protection, this would be the reason to use a manual starter. If you want a remote Start or Stop control you need a magnetic starter.

    Hope this helps
    Stan

  8. #8
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    5,606
    I would mount that switch box out 5-6 inches so it just almost sticks out from the front edge of the table. Stack up some 2x4 to get the distance needed. Drill a good size hole for the wires or use conduit. It is much easier if you can see the switch from the operators position or hit it with your knee, thigh or hip with your foot safely on the ground.
    Bil lD

  9. #9
    Join Date
    Apr 2017
    Location
    Michigan
    Posts
    1,617
    This is may be the right time to upgrade your new saw. Here's what works for me.

    vfd.jpg

    I've added a VFD and 1800 rpm motor and foot switch.

    Slower speed makes the saw much nicer to use and safer. Instead of a tip speed of 100 mph I normally run at around 40 mph. Sure some cuts take a few seconds longer, I'm not running production. I set the stop time to 1 second, that's handy. Start time is 1 second also, no big power surge to dim the lights.

    The foot switch makes it easier and safer to start and stop the saw. There is a second switch to cut power to the VFD for times when the saw will not be needed.

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