I have a 20 year old 10" Craftsman table saw with a 13A/1.5HP (3HP
I am finding that the saw seems to bog down when ripping even 3/4"
plywood (let alone hardwood) despite the fact that the saw is now near
perfectly aligned (via a dial-indicator) and I have upgraded to
machined steel pulleys and a link belt.
Part of the problem may be due to the fact that the upgraded pulleys
are 2.25" and 2.5" vs. the original 2.5" and 2.5".
But that aside, how hard and expensive would it be to upgrade the
- Any suggestions of where and how I could find a good motor (and be
sure that it is a quality replacement)?
- Could I get a (meaninfully) more powerful 110V motor (it is on a 20A
circuit) or would I be better off getting a 220v motor?
Anything else change like the location and/or the outlet/extension
If I'm using this calculator correctly you could be loosing about 10%
at the blade with the pulley change.
Is the blade clean and sharp?
As mentioned by some one else, make sure you are not using an extension cord
and or use one that is of proper gauge and length.
I had the same problem on a 1983ish model 1 hp Craftsman. I simply aligned
the saw and put a sharp good to premium quality blade on the saw.
I would suggest going to a premium quality saw blade, the Forrest WWII
"regular kerf" 40 tooth would not be a bad choice. Regular kerf because I
learned a premium quality regular kerf blade will cut faster than a lesser
quality thin kerf blade. The regular kerf will yield better results than
the thin kerf also.
If you still need help go to the bigger motor. The blade will be a great
investment regardless if you still have to upgrade the motor or not.
If the motor can be reconnected to operate on 240V, do it.
If not, replace motor with largest 56 frame, 240V motor that will fit
and use existing motor for another application.
Trying to operate a T/S at 120V is a down hill adventure.
It's a loser all the way.
Most certainly. Are they arranged so that your blade is spinning
faster (hence less torque available) or slower (more torque)?
What kind of blade are you using? That could make all the difference.
Do you rip with a rip blade, combination blade, or what? Thin kerf?
Carbide, I assume? Is it sharp?
With your contractor type saw, you could perhaps upgrade to a 2 HP
motor, and probably not a 3 HP. Is that extra 1/2 HP meaningful?
Marginally, I'd guess.
A 2 HP 110V motor would likely trip your 20 amp circuit breaker now
and then, by the way. You'd be better off using 220V, or a 30 amp
circuit (which means 10 gauge wire).
Grizzly sells motors and I suppose they are the same as in their table
saws. I've never heard anybody complain about their motor quality. I
have several Grizzly tools and they serve me well.
Here's their catalog page with motors listed.
You'd be looking at $240 plus shipping, I think.
I wouldn't do it, without first making sure about the blade(s) I am
Assuming your saw did not bog down before your changes ...
Then the upgraded pulleys are the logical culprit.
If the 2.5" pulley is on the motor then you are now spinning the
blade faster than it originally did and the available torque is less.
Try putting the 2.25" pulley on the motor. The blade will spin a
bit slower but the torque will be higher. This will make it less
likely to bog down but your feed rate will be a bit slower than
"blueman" wrote ...
For what it's worth, I have a very small Delta table saw (TS-350) with
a 1 hp motor. It cuts 3/4 hardwood ply, 1.5" oak, etc. with
absolutely no problem. It's well aligned and I use a sharp blade. It
seems your problem should be solvable without going to a larger motor.
No. You would be marginally successfully running a 2HP motor on a
120v/20A circuit. You could do it, but expect frequent nuisance trips
when exercising the saw at its maximum power.
without a doubt!
But before you do anything, you should determine conclusively what is
causing the low power of your saw. A number of things to consider have
already been suggested. If you're running through an extension cord,
that's the first place I'd look for the problem. Running 12 to 14 amps
through a small gauge extension cord will definitely choke down the
power available from the saw and likely cause a few breaker trips as
3/4 stock should not present a problem to a clean, sharp,
well-aligned thin kerf blade on a 1.5 HP saw.
Agreed. Running my 1.5 hp saw on a 25 foot 14 gage cord and a 15 amp
circuit it bogs during rips. Running it on a 12 gage cord and a 20
amp circuit it doesn't. Eventually it's going to have its own 220v
A 12 gage extension cord isn't horribly expensive and even if it
doesn't help the saw problem it's a useful thing to have, so if it's
on an extension cord that would be the first thing to try IMO.
Every Craftsman saw I've seen except the very cheapest ones can be
rewired for 220 just by moving a few jumpers and changing the plug.
Before buying a new motor I'd suggest trying to obtain a copy of the
manual--you might have to do it in two steps--get the saw manual, find
out what motors it took, then order the motor manuals. Check the
motor and see if it has its own model number and if so you can get
both the saw and motor manuals at the same time, if they're in stock.
If the saw manual says "don't rewire for 220 even if the motor can be
rewired" it's likely because their power switch only opens one leg of
the circuit, which with 220 means that there's juice in the saw even
with it turned off--if you ever need to poke around inside it and
forget to unplug it you can get a shock--you can take your chances or
you can order a 110/220v power switch from Grizzly for 15 bucks or so
plus the cost of a handy box.
OK - a couple of follow-up questions:
1. The manual says "It is wired for operation on 120 volts, 60 Hz
alternating curent. IT MUST NOT BE CONVERTED TO OPERATE ON 23)
Is this warning just do to the fact that the switch would be
dangerous (unless it too were converted) as you mention above or
could there be something fundamental about the motor here?
Note: it was one of the higher end saws (about $500) when purchased
about 17 years ago.
2. I could not find any reference to the motor by googling on the
net. Again the specs on the motor are:
Mfg Model: T55HK-499
Also, when I called Sears they couldn't help me out. Any thoughts
on how I could verify that the motor is rewirable and then what I
need to do to rewire it?
3. How big is the power "boost" when taking a given motor and rewiring
for 220v? Will the difference be significantly better than just
using 12 gauge vs 14 gauge cords?
i.e., will the difference be big enough to make the rewiring
There is no power boost to the motor from the rewiring. Actually, the
coils inside the motor see exactly the same voltage in either case.
The coils in a dual-voltage motor are connected in parallel for the
low voltage case and in series for the high voltage configuration. The
voltage drop across each set of coils is the same in either case.
The only "improvement" from rewiring a dual voltage motor for high
voltage comes from a reduction in the amperage flowing through the
wiring that feeds the motor. The amount of transmission loss (voltage
drop and power loss) is a direct relationship with the amperage.
Double the amperage and you double the voltage drop in the wiring from
the transformer to the wall socket. Since the power dissipated in the
transmission lines is a function of amperage squared, doubling the
amperage increases the lost power by a factor of 4. Likewise halving
the amperage reduces the power loss to 1/4. However, this is only
significant if the power loss at low voltage is significant. In the
majority of installations, it is not.
In a few cases, transmission losses can be significant enough that
going to a high voltage configuration will show a noticeable
improvement in the motor performance. This can be seen most frequently
when the motor is at the end of a high resistance wiring path; either
very long wire runs or light gauge extension cords. It is most likely
to be apparent in the motor startup. Since the amperage draw is much
higher during startup cutting the loss in half can significantly
affect the power available to the motor during the startup.
With that said, a direct answer to your question about whether it's
worth it or not, is a big "maybe, but not likely". If you run the
motor off of a long, light gauge extension cord, then you'll probably
see a significant improvement. If your wiring is near code limits for
voltage drop, then you may see noticeable improvement. In all other
cases, it will be difficult to detect any difference in the motor
I am running on a 20A/12 gauge circuit but I am using a "heavy duty"
outlet strip with a 9 ft 14gauge cord (note nothing else is used on
the circuit when I run the table saw). Also, I noticed that the table
saw itself has about 6ft of 14 gauge wiring after the switch and maybe
another 3-4 feet between the motor and the power switch.
Would I likely notice a *significant* difference by replacing the cord
on the saw with 12 gauge and using a 12 gauge extension cord or outlet
strip? All-in-all I would be replacing about 15-20 ft of wiring
AWG 14 copper wire has a resistance of .002575 ohms/foot. AWG 12 is
.001619 ohms per foot.
(Ref. http://www.interfacebus.com/Copper_Wire_AWG_SIze.html )
Replacing 20 feet of 14 ga wiring with 20 feet of 12 ga wiring
(actually 40 feet of conductor) would reduce the wiring resistance by
.03824 ohms. Assuming a 15 amp current, you would gain about 0.57
volts at the motor. Significant? Probably not. However, during the
startup surge you could be drawing on the order of 90 amps for a short
period of time. Under those conditions, you'd gain about 3.4 volts at
the motor. That could make a noticeable difference in startup
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.