Any way to run a 12" jointer on 115 volts?

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Forum topic by Cole Tallerman posted 09-10-2012 02:11 PM 1895 views 0 times favorited 9 replies Add to Favorites Watch
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Cole Tallerman

392 posts in 2357 days

09-10-2012 02:11 PM

So I’m building a 12” jointer from but the plans call for a universal motor. A universal motor has lots of power in a small package that runs off a 115 volt outlet. The only downside, is that they are unbearably loud. I would like to use an induction motor instead, and i know that the biggest motor that can be run on 115 volts is 1 1/2 hp (is this correct?). So my question is this. Would a 1.5 hp motor be enough to power a 12” jointer? IS there any way to run a bigger hp on 115 volts? (maybe with a 30A outlet?)



9 replies so far

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Bill White

5101 posts in 4132 days

#1 posted 09-10-2012 02:21 PM

Today’s HP ratings are bogus. The amperage draw is the important number to study. An induction motor that draws X amps running will have a surge draw on start up. A 20 amp breaker is about the most I’d use on a 110v motor, and it would probably need to be a seperate circuit.
The jointer would probably work with a “1 1/2” HP motor if ya don’t try to be a Paul Bunyon when jointing, and have sharp blades.
Is 220v out of the question?


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Cole Tallerman

392 posts in 2357 days

#2 posted 09-10-2012 02:33 PM

I have one 220 volt 40A outlet for a welder. Could I put a 40A plug on the motor even if its only drawing like 10A?

View Grandpa's profile


3261 posts in 2847 days

#3 posted 09-10-2012 02:34 PM
This link will take you to a 2 HP electric motor.
That is the greatest HP I find. If you use a 30 amp circuit you will need to run a new circuit and wire anyway so why not a 220 V as Bill suggests. Then you can get a lot more HP if you want. 30 amp 110V receptacles are available from camper supply places. everything would have to be special. Can’t just plug a 15 amp plug into any receptacle and call it good. Most plugs are rated for 15 amps. 20 amp receptacles are more readily available but still that isn’t good enough. No point in burning the shop down. I have an air compressor that I run on 110V that claims to be 2.5 hp but I doubt that. It will ocassionally trip a circuit breaker. I don’t use it anymore. We run 6 inch jointers on 1/2 hp motors so I would think a 12 inch would operate on 1.5 hp.

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3261 posts in 2847 days

#4 posted 09-10-2012 02:39 PM

sure you could put a 40 amp plug on the motor and draw 10 amps. You want everything to be able to handle more than the maximum rated amperage except the fuse or circuit breaker. That must be rated correctly so the motor doesn’t start smoking. Where we get into trouble is when we use a plug that is too small. It will heat up and things get dicey.
If that 40 amp receptacle has a 40 amp circuit breaker than that would need to be changed to match the motor requirements. The wiring for the 40 amp circuit could be retained and used for the jointer. Just get a breaker that is manufactured by the same folks that manuf your panel and you shoudl be good.
A moptot will draw a certain number of amps. The circuit cannot force more amps into the motor than it will use. The motor determines what it needs for a certain job. If the breaker is too large and we over load the motor we could damage it. The breaker protects the circuitry in the wall and should also protect the motor but it HAS to protect anything we have enclosed. The cord for your jointer is in open air and it is less likely to burn. Think about a lamp with a 60 W bulb. I don’t know how many amps it draws but it is low….like 5 amps. We have it on a circuit that has a 20 amp breaker and it usually has a small cord that will carry 10 amps. The wall receptacle is normally a 15 amp receptacle. The wiring is 12 ga so it will carry up to 20 amps safely but it is enclosed in the wall. Get a licensed electrician to run that wiring and install the proper circuit breakers for you. It won’t cost you much. Might be cheap in the long run.

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Cole Tallerman

392 posts in 2357 days

#5 posted 09-10-2012 02:47 PM

Thanks everyone for your responses! Grandpa- There is no more space on my panel so it would be to costly to have the whole panel replaced. I may just try to find a cheap 1.5 hp motor on craigslist. if a 6 in jointer will run on 1/2 hp then 1.5 hp could defiantly power a 12” jointer. Thanks everyone!

View Dusty56's profile


11822 posts in 3860 days

#6 posted 09-10-2012 02:56 PM

I have an antique Powermatic 8” jointer that has a 3/4hp motor in it….Plenty of power to spare.
Assuming MOST of your jointing should be between 1/32” and 1/16” , you should be fine. If you’re going to be a production shop and flattening a lot of roughsawn lumber, you might want to step up the HP.
220v would be the way to go…a lot more options to choose from : )

-- I'm absolutely positive that I couldn't be more uncertain!

View wunderaa's profile


248 posts in 2374 days

#7 posted 09-10-2012 03:19 PM

To Bill’s point, Craftsman and others have historically inflated their motor ratings, so you have to be aware of that when shopping for tools. The largest 110V motors that I’ve seen are rated at 2HP nominal load. If you were to go with a 2hp unit, I would recommend changing the breaker to 30A because of the current in-rush at startup.

While shopping around for a motor, you’re more likely to encounter a plethora of 1.5HP units. You’ll be looking for a 3450rpm, TEFC (Total Enclosed Fan Cooled – to protect from dust intrusion) unit, any slower and you’ll have to play around with pulleys too much. If you’ve followed along at, you’ll notice that he talks about the main drawback of the unit being that it bogs down. This is because the universal motor that he used (from a lunchbox-style planer) has very little torque. Those motors run at 20,000 rpm and rely on the inertia of the cutter head to plow through tough sections. But under continuous heavy load, they cannot recover. Going to an induction motor of 1.5HP (IMO) will solve a lot of those issues.

If you plan to join wide stock often, then I would seriously consider running a larger motor (3HP, still at 3450rpm) and utilizing a dedicated 220V breaker. That will ensure that you always have the power you need.

Looking at specs for most joiners, it appears that most units run with a cutter head speed of 10-15,000 CUTS per minute. With that in mind, you’ll need to do some pulley work. If you get a 3450rpm motor and your cutter head has 2 knives (like my planer does), then a 2:1 (motor-to-cutter head) pulley ratio will get you where you need to be. Therefore, if your cutterhead pulley is 2”, you’ll need a 4” motor pulley to get you in the middle of the range (13,800 cuts per minute in this case).

Hope that helps.

View knotscott's profile


8137 posts in 3547 days

#8 posted 09-10-2012 03:37 PM

I can’t see why it wouldn’t work on a 12” jointer….take shallow passes if necessary.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View crank49's profile


4032 posts in 3143 days

#9 posted 09-10-2012 05:22 PM

Of course. You can get 5 hp motor that runs on 115 volts if your pockets are deep enough. But, why?
2 HP draws ~18 amps on 115 v.
3 HP draws ~26 amps on 115 v.

In either case you might need a bigger breaker than indicated. Inrush current to start a motor is 4 to 8 times the running amps. A slow trip 40 or 50 amp might be needed to start that 3 HP for instance. Depends on the motor. The wire and outlet have to match the rating of the breaker regardless.

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