craftsman 113 upgrade

Paul...not to be argumentative with your comment (I'm not an electrician), but here is my understanding (wrong or right)...

example of a motor wired either 110 or 220

110 volts x 15 amps = 1650 watts (one leg at 15 amps)
220 volts x 7.5 amps = 1650 watts (two legs at 7.5 amps each)

They both equal the same watts …. 1 HP = 746 watts

My 2HP table saw is wired 110 drawing 16 amps and is on a dedicated 20 amp circuit. If I upgraded my electrical to 220 and not rewired the motor to 110, my saw then would draw 8 amps.


Sawdustjunkie Hope an electrician will post a definitive answer for your situation and to further educate myself with this question

Not sure what motor I have hanging off the back of my 113

Still wired for 110v. It is a bit larger than the OEM was

I take it that this saw is like yours

I turn it on, hear a thump (belt) then just the sound of the saw blade cutting the air.

Mine might be a bit wider, though

2hp is about the largest I'd go with…the supporting mechanisms simply aren't made to handle much more weight and torque. 2hp is also about the upper limit for most residential 120v circuits without needing to go to 220v…..and as Paul mentioned, it's likely to be closer to 1.75 usable hp. It's possible that your 120v circuit isn't quite up to snuff. Is your current motor switchable to 220v? It's not as likely to make much difference on a motor of that size, but it'll only cost the price of a new 220v plug to try it.

Good thin kerf blades are a good start, but the tooth configuration is also important. Something like an Irwin Marples or Freud Diablo 24T should have a relatively easy time on a saw that's well aligned and setup properly (check pulley alignment, belt tension, etc). Wood is much easier to cut if it's flat, straight, and dry. If a good sharp low tooth count blade and a good tuning don't help much, a motor upgrade might help, but I wouldn't spend a lot of time and money trying to make the saw into something it's not.

Let us know how you make out.

Equating watts to HP is tricky. The big problem is that motors are an inductive load. That P = V X A equation only works for resistive loads with a "power factor" (pf) of 1.0. The full equation is actually P = (V X A) X pf.

The 1 HP motor on my 113 (this is "real" HP, not the inflated claims made by "peak" HP which gives that 3HP rating mentioned earlier) states on the motor plate that it draws 14A at 110V full load. A little quick math would seem to imply that it takes 14 X 110 = 1540 watts to deliver 1 HP. That is not quite true - induction motors run at a pf of ~ 0.5 which means that the voltage and current are not in phase and the actual power developed is less than a straight P = V X A would indicate. You won't get charged for more power, power meters compensate for this, BUT your wiring MUST support the increased current required by the inductive load to deliver actual 1HP.

Assuming a 2HP motor is similar, this probably means that the current draw for a 2 HP motor will be around 28 A full load. The most you should pull through a 110V outlet is 20 A which will limit you to a 1.5 HP motor - and that would be marginal.

None of this touches on starting current (which can be as high as 5X the fl current) OR NEC regs which call for derating motor circuits. I'll leave all that for another time. Suffice it to say that I won't be running more than a 1HP motor on 110V in my shop.

Now, some notes on line quality. I just rewired my shop 2 summers ago. I have the 1 HP motor on my 113 that I mentioned above. It always seemed a little anemic to me. When I rewired, I pulled heavier feeds to my garage, installed a subpanel and ran a dedicated 12 AWG circuit to the saw. It was like a new saw.

Pay attention to the wiring! Do NOT run the saw on an extension cord. Any resistance in the line to the saw motor will decrease the available HP, lead to longer startup times and, contrary to intuition, actually increase current draw by the saw motor. After researching this stuff before wiring my shop, none of the 110V circuits in my shop are less than 12 AWG even though most of the tools in my shop are much less than 1 HP.

Ya know since Sears sold a slew of these TS's there in the 70's and 80's and well since, there have been boo Koo discussions on various groups, just what to do to make them better. I bought mine in the mid 70's , and during all of this time IMO have spent way too much time realigning the trunnion/arbor/blade, compared to a good friends Ridge TS. Back close to new, I added a balanced pulleys and link belt, which add a lot, then I had ran its own 12/3 wire attached to a slow blow 20 amp breaker. But all along I though that if ever that motor went out so would that whole saw.
It did and I did not, when it finally happened I thought I would check on the price of what was advertised at one of the bigger local new motors and rewind shops, as a new 110/230/2hp. bought one, and ZOOM ZOOM, that was the biggest/best improvement I could have made. It amazed me, on how I had got use to in all of this time, babying a gimpy motor on that TS, World of a difference.
Had to make several changes though, one of the biggest was that this motor was larger to began with, then has this bell atachment that sticks out from the body surroundsing the upper half. When cranked up while cutting at a 45, it barely is below the TS's steal top. So had to re due the out feed table. Re wired with heaver wiring, to the switch then to the plug-in on the saw also.