Switch for Old Unisaw

[Thom Porterfield]

The saw is older than I am...it was made in 1946...and it's seen many better days. Still, it will see many more good days. I'm not interested in restoring it to original condition--just want to ruin wood with it in the best possible fashion.

When I inherited the saw, it had the original motor on it. For me, it worked fine. But there was a period where I wasn't doing woodworking and a friend was, and he asked to borrow the saw to use as a dedicated dado saw in his cabinet shop. I agreed. He replaced the original Delta fence with a Biesemeyer and side extension table. He also installed a new 3-HP motor (this required cutting away part of the cabinet, which didn't seem so awful at first, but now...oh well, damage done).

Thing is, the original owner of the saw (my dear departed dad) had the machine installed in a huge work table (about 16' x 12') and had reconfigured the on-off switch. It is a standard toggle switch in a 4" square metal box (yeah, like the one on the wall in your house). When the saw left the big table some years later (but before I got it), that box was screwed onto the sheet metal cabinet. It's still there, and adequately, if not terribly safely, turns the motor on and off.

I really would like a better switch situation. You know, guards around the push buttons, big paddle to kill the motor, etc.

Suggestions? Make and model of switch, installation location, etc.
Thanks.

[Pete Bradley]

The original toggle switch, switch box, and the original bullet motors are all in some demand, so if you're not using them, put them out on eBay and you'll finance this project with money left over for more wood to ruin. :)

[Thom Porterfield]

Wish I had them, Pete. The OEM motor disappeared when the new motor was installed. I never saw the OEM switch/switch box. It was apparently common in my dad's shop to replace the switches on power machines with "more convenient" switches. He disabled the switch on the old Craftsman DP (located on the motor bracket) with a toggle switch in metal J-box attached to the C.I. shroud above the quill.

The switch mod on the DP is fine (sorta) in that it's actually way more convenient than the OEM solution. However, reaching under the table of the Unisaw to find a small toggle switch while the saw is potentially in kick-back mode is "Not A Good Thing."

The Unisaw is right tilt, the switch is mounted on the cabinet above and to the right of the blade height adjustment wheel. My thought is that it would be WAY safer if the switch was mounted just under the fence rail on the left side...but would that get in the way of reading the tilt angle gauge?

And I really do not want to continue with this little toggle switch to operate such a powerful machine.

[Josiah Bartlett]

You could use a Grizzly H8242 (they are on sale for $10 right now), or put a magnetic switch on it, or go with a vintage thermal overload switch/motor starter.

[Scott Schwake]

I bought one of these I'm planning to install on a similar vintage Uni:

http://www.safetyonline.com/product.mvc/Easy-Off-Power-Control-0001

[george wilson]

The guy altered your saw without asking you about it? I'd have been furious to lose the bullet motor.

[Stephen Cherry]

The guy altered your saw without asking you about it? I'd have been furious to lose the bullet motor.

I agree, he should have asked, but the new fence seems like a big plus. Plus, was the old motor capable of turning a wide dado?

There are lots of opinions on what to do with old machines, but adapting to advance with current technology does not seem so wrong, particularly if it maintains the usefulness of the machine.

That said, something like this:

http://www.grizzly.com/products/110-220V-Paddle-On-Off-Switch/H8243

would allow the saw to be turned off with your leg during operation.

[Thom Porterfield]

The guy altered your saw without asking you about it? I'd have been furious to lose the bullet motor.


I agree, he should have asked, but the new fence seems like a big plus. Plus, was the old motor capable of turning a wide dado?

"The guy" is a dear friend of mine. He did ask and I gave permission. I was unaware (then) of the value of the old saw. It was only when I took it in to a shop for a tuneup that I found out what a gem I have. The old motor, if I recall correctly was a 1-horse motor. My friend, who runs a large cabinet shop, wanted to install the new motor because the original one wasn't powerful enough.

And yes, the new fence and side table are, for my needs, superb. I feel I got the better part of the bargain, despite the loss in historic value of the saw.


There are lots of opinions on what to do with old machines, but adapting to advance with current technology does not seem so wrong, particularly if it maintains the usefulness of the machine.

I agree. I've already retired the original miter gauge in favor of a Kreg. Whereas before, I went out of my way to avoid using the miter gauge, now I use it all the time. And I'm eager to begin making and using some of the very cool jigs I read about in the magazines.

Thanks, to Scott and Stephen, for the links.

However, neither of the sources adequately describes mounting methods. I am not very eager to inflict further damage to the Unisaw--is there any way to hang either of those switches from the Biesemeyer support angle?

[Stephen Cherry]

I think the one I posted mounts in a normal, home depot style electrical box, which could be mounted anywhere with a little imagination.

[Josiah Bartlett]

There's plenty of room on a Biesemeyer angle iron to mount a variety of switch boxes- just drill and tap.

[Scott Schwake]

"However, neither of the sources adequately describes mounting methods. I am not very eager to inflict further damage to the Unisaw--is there any way to hang either of those switches from the Biesemeyer support angle?

How about something like this? (credit to jeffro over at OWWM)

[Dave Cav]

there any way to hang either of those switches from the Biesemeyer support angle?

I have used several of the Grizzly paddle switches and they seem to work fine. They can be mounted in a standard 4 square box using an adapter faceplate for a duplex or light switch , then hang the 4 square box from the Bies rail or tube either directly or with a piece of angle iron.

[Josiah Bartlett]

Since the original poster started this thread back in August, hopefully he has come up with a solution by now.

[Mike Cruz]

Oh, come on Josiah, there have got to be 2 or 3 more options we can give him to regret whatever he did back in August. Where is the fun at leaving someone satisfied with their decision? Pulling out the old threads with a "Oh, I HOPE you did X and not Y, because of Z" post WAY after the fact is half the fun. :D I have to admit, I was thinking the same thing when I saw the date of the OP.

[Chip Lindley]

And I really do not want to continue with this little toggle switch to operate such a powerful machine.

And that was the OP's last thought...nobody knows what he opted for. Here's my option for a 3hp 230v motor:

Few "on/off toggles or pushbutton switches are rated for a 3hp/230v motor. And you only have the overload reset button on the motor (if so-equipped) to protect it from overheating.

I am big on installing magnetic starters on every machine in my shop. There is a extra safety factor with mag starters, in that the motor will not accidentally restart itself if power is interupted and then restored. And, their overload heaters add extra insurance to keep from frying an expensive motor. Besides that, I just think mag starters are cool! (I made my own low-voltage mag controls from junk HVAC parts wayy back in the 80s)

There are many decent mag starter bargains now on ebay if you know what you are looking for. A Size 1 starter, either 3-phase or single-phase will do. Magnetic coil for 120v or 240v. At least one overload heater sized for your motor's max. amperage (FLA). The pushbutton station can be on the starter box itself, or as a separate control conveniently placed.

The "panic paddle" is a good idea for emergencies when you need to stop the machine NOW. I see no momentary paddle on/offs offered by Grizzly, Rockler or others, but any momentary can be rigged with it's own STOP paddle. Necessity is the Mother Of Invention.

[Thom Porterfield]

Sorry to all of you who offered good advice. My grand plans on upgrading my shop took second place to other endeavors, some of which were not so grand, and some that were very grand indeed. But now I'm back to it, and just this week finished revamping the switch on the saw.

I found this: http://powertecproducts.com/71007-110-220v-paddle-switch/ and devised a way to mount it below the Bies fence, similar to the solution posted above by Scott Schwake (https://sawmillcreek.org/member.php?3647-Scott-Schwake) but using existing bolts. It works fine. . . . But I don't...I keep reaching for the now non-existent switch under the table. I'll get used to the new location, and I really DO like the panic paddle to turn the saw off.

One of the problems with the modification my friend made was that the oval hole for the original bullet motor was now huge, and had no cover. Needless to say, the result is that almost as much sawdust wound up outside the saw as piled up inside the cabinet. So I made a box of some scrap hardboard as a test for a future sheet metal solution. But the hardboard works great, if somewhat ugly, so the sheet metal solution may not happen for some time.

Anyway, guys, thanks again for all your advice. It's good to have sawdust in my hair again and Titebond under my fingernails.

[Jacob Reverb]

You could use a Grizzly H8242 (they are on sale for $10 right now), or put a magnetic switch on it, or go with a vintage thermal overload switch/motor starter.

I put one of those on my Powermatic and love it. It's nice to have the paddle you can hit with your knee (or whatever) when you're wrestling a sheet of plywood or whatever and need to shut the saw off in a hurry without looking for the switch.

https://www.bing.com/th?id=OIP.3vntCNvrLeFtXGL0u-UpsAAAAA&w=212&h=212&c=7&o=5&pid=1.7

I had considered fabricating something along the same lines, but it was so cheap that it'd be stupid to waste my time.

[Don Jarvie]

Nothing wrong with a “light switch” as long as it’s rated amp wise for the motor. Some find the paddle more convenient so it’s up to you.

[Bob Vaughan]

When switch shopping, don't forget the unavoidable condition called inrush current. "Experts" won't agree on how many times more amps the inrush is than the rated running amps, but three times is conservative. Say you've got a 3 HP single phase motor that's rated for 14 amps at 230 volts. Inrush will be 42 amps if not significantly more. The switch's contacts need to be sized to sustain that kind of arcing during power on and off cycles. For a single phase motor, there's also the added draw to charge the capacitors.
Light switches are for resistive loads and not inductive loads like motors. Using a light switch will work for a while but it doesn't do the components any good and those tiny contact points of a light switch get corroded quickly and let less and less electricity flow over time. Fortunately single phase motors have capacitors that fail before the windings burn out when one is using a switch with tiny contacts.

The optimum motor starter size for that motor would be a NEMA size 1. The contacts in those plastic box mag starters from Asia aren't a whole lot bigger than light switches. They just play fast and loose with what amp ratings they print on the labels.