# Question: buying new motor for jointer....



## ChuckEmmons (Jan 9, 2008)

First, I'd like to say hey to everyone. I've been sort of a lurker here for a while now, but have been pretty busy trying to get my garage shop setup.

I recently bought a 6" craftsman jointer off a friend for 50 bucks. It was manufactured in 1976 and has a 1725 rpm 1/2 hp induction motor. It also has 3 blades. My friend told me that he only used it a few times but that the motor wasn't very strong if he could remember right. I haven't been able to test it out yet because it needs a stand to mount the motor, so I'm going to buy a new motor and design a jointer cabinet to attach it to with a chute to guide the chips to a dust port (I'll post the project when it's done).

I was thinking about picking up a 1 1/2 or 2 hp induction motor and was wondering if I should stay with the 1725 rpm or could I go with a 3450 rpm? The pulleys are 2" at the jointer and a 4" for the motor. This would equate the jointer going from 3450 rpm to 6900 rpm. Would this affect the safety or life of the jointer?

Any advice is appreciated. Thanks.


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## lew (Feb 13, 2008)

Personal opinion, for safety, stay with the same RPM.


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## Karson (May 9, 2006)

I might have the same jointer. I'll try to look at what I have. I'm guessing it's 3450. I've not used it in about 3 years.


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## bendisplays (Feb 2, 2009)

Chuck,

If you go with a 3450 rpm motor, then you will have to reduce it with the pully. Your jointer has been designed for a specific speed. Also the bearings are designed for a specific speed and may not be able to take a doubling of the rpm.

A good way to think of what you will be doing is to create a perspective. The diameter of a jointer can easily be 3" or more. So the velocity of a jointer running at 6900 rpm is the same as a 1/2" router running at 41400 rpm. Your jointer is also taking up to a 4-6" cut (or larger if you have a larger jointer).

I would up the horsepower of the motor so it wont bog down but I would stay at the same rpm (1725).

Cheers,

Ben


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## marcb (May 5, 2008)

Either way you go in terms of RPM replace the motor pulley to get the cutterhead speed to 4000RPM or so, keep it under 5000.

Also 1 1/2 HP is way overkill for a 6" jointer. I have a 3/4 HP on mine and can't bog it down with 1/8" cuts across full face which is pretty deep for jointing.


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## Porosky (Mar 10, 2009)

Keep the same RPM. Up-grade the Horse Power. HP=Happiness


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## ChuckEmmons (Jan 9, 2008)

Thanks for the advice so far!

SO…. it appears all would be well if I stick to the same rpm and go with a 1 hp motor… I plan on using mostly hardwoods with it, so I don't want to get stuck on the low end with the power. I've read that the hp rating isn't always reliable, so I was thinking a little over-kill won't hurt in this area.


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## marcb (May 5, 2008)

It doesn't matter which RPM's you go with because you really need to get the cutter head into the 4500RPM range, which means buying a pulley of the right size.

If you get a 3450 RPM motor you need approximately 2.55" OD pulley (standard size, easy to find). Which can be had for about 5 bucks, pretty cheap way to ensure the machine works like it should.

Sticking with the slow speed at the cutter head that you have now means less force being applied to the cutting edge meaning more chatter. If you do stick with 1725 RPM motor you ill need a 3.15 OD pulley (closest standard size). buy online, get cast iron pulleys. Stay away from the diecast aluminum stuff found locally.


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## rickthumbs (Mar 3, 2008)

I just bought a new Marathon motor through eBay for $15.00. The local motor store wanted $150 Mine was 3450 rpm, single phase, 1/2 HP. I upgraded to 1HP, same RPM. Hope that was right. Haven't hooked it up yet. Question for you electricians: The original motor had a black & a white wire. This has blue, red, orange, black, white, yellow. The wiring diagram on the motor has 2 configs, 1 for "low power", one for 'high". Assuming low power is 110V & high is 220, the setup for 110 is blue, red, orange connected together for 'line 1' , and blk, white yellow together for line 2. ! question is why were the blk, white orange wires twisted together from the factory. Should I go with the lo power config, & what about a ground wire? I emailed the company, haven't gotten a response yet. Bet you LJs come up with an answer before they do. 
Thanks folks


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## freedhardwoods (May 11, 2008)

"why were the blk, white orange wires twisted together from the factory?"

If the motor is reversible I would say it is wired in reverse of the diagram you are looking at. If not, I would guess it was wired for 220. Can you give more info about the motor? Is it reversible? Does it have a 220 diagram? Where does it say to fasten the incoming wires (110 & 220)?

As for the ground, you will need to supply that with the incoming wire. There should be a screw to fasten the ground wire to under the cover plate.


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## marcb (May 5, 2008)

If all 6 leads are brought out the motor is reversible. If only 4 are it is sometimes depending on if the other 2 are start leads or not.

You can't be sure what wire does what without confirmation with an ohm meter and some diligence. I don't have the book with me that explains how to do the tests exactly. I can dig up more in Electrical Motor Repair if you need it. But I'm assuming Marathon will get back with you monday if you are still confused.

I would wire it the way it says, assuming this is a single phase capacitor start dual voltage motor low == 110. If it spins the wrong way reverse to the way it came wired.


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## BlankMan (Mar 21, 2009)

Chuck,

It appears with the pulleys you mentioned the cutter head is already spinning at 3450. The fact that by the pulleys you're increasing the speed you're also reducing the HP/torque, probably why your friend said it was probably a little weak at cutting. If you increase the horsepower and increase the RPM then use equal diameter pulleys you'll stay at the same cutterhead RPM but you'll see the rated HP/torque at the cutterhead, now you're not.

I'd consider upping the motor speed then adjusting the pulleys so that you stay within the rated RPM of the cutterhead and bearings. Faster cutterhead speed means more cuts per minute thus a smoother finish. The cutterhead on my DJ-20 spins at 5500 RPM, 16,500 cuts/minute.

You'll have to do some digging to get the specifications of the cutterhead and bearings if that's even possible. If the bearings maximum RPM is less then the cutterhead you might be able to then replace the bearings with higher RPM bearings.

It'll cost to do that so you have to decide if it's worth it to you. Worst case you could also replace the cutterhead and bearings with a set rated at a higher RPM. But like I said it will cost so it's up to you if it's worth it.


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## ChuckEmmons (Jan 9, 2008)

Thanks to everyone for the thoughtful replys. I guess it's time to look for a motor and bearings now.


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## BlankMan (Mar 21, 2009)

Chuck, since I see you're from Wisconsin, Mill's Fleet Farm or Blain's Farm & Fleet might be a good place to look for a motor if you have any near you. I picked up a 1HP Marathon motor for my drill press a bunch of years back but don't remember what it cost.

Again, based on you're locale, I was at the Northern Tool store in West Allis this past week and they had a 1HP 3450 RPM Leeson motor on the clearance shelf for $129. It might be gone because yesterday they had their big 10% off store sale and when I stopped there the place was packed and I think I saw it on one of their outdoor parking lot table displays. If that's too far for you but you'd consider driving there for it I'd offer to stop and see if it's still there before you did if you want.


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## ChuckEmmons (Jan 9, 2008)

Curt, Thanks for the advice. There's a Fleet Farm and Farm and Fleet near by. I'm near Madison, so Northern would be a road trip, but based on what I see at the other two, that might still be a savings.

Btw, your advice on the motor/bearings was excellent. I plan on doubling the rpm and upping the hp to around 1hp with a new cutter head, bearings, and pulleys. The jointer is in good condition and I got it cheap. Since I have to build a cabinet for it, I might as well do this so I can get some good use out of it.


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## BlankMan (Mar 21, 2009)

Thanks. Chuck from Madison? Would that be COP by chance?


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## jleiwig (Jan 29, 2008)

The size of motor to use depends upon the demands to be made upon the jointer. The following general classifications should be followed when choosing a motor for your electric jointer.

Type of Duty Horsepower Required
Light 1/3
Standard 1/2
Heavy 3/4 or 1

The common operating speed of 6-inch jointers is about 3500 rpm. This nay be obtained on the 6 inch jointer by using a 5-inch diameter pulley on any standard 1750 rpm motor. Should you desire to obtain a better finish or to get more production, you may operate the jointer at 4200 rpm. To do this, use a 6-inch diameter motor pulley. However, keep in mind that this higher speed may require more power.

The above was pulled directly from the owners manual of my jointer. If your jointer has a 2" pulley on it, you can use either a 5" or 6" pulley on a regular 1750 rpm motor. Look for a TEFC motor if you can. I'd say that 3/4 HP will be more than enough for a hobbiest use. If you were a production shop I'd look bigger.


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## Orleck (Mar 14, 2018)

I've got his same jointer, and even at 1/32nds cuts on a 1×6 pine board mine can't handle it, everyone i know says 1/2hp is way too little for a 6" jointer, but based on what you say I'm thinking maybe there is something else amiss with the jointer perhaps? If i don't need to replace my motor I'd rather not. any advice?



> Either way you go in terms of RPM replace the motor pulley to get the cutterhead speed to 4000RPM or so, keep it under 5000.
> 
> Also 1 1/2 HP is way overkill for a 6" jointer. I have a 3/4 HP on mine and can t bog it down with 1/8" cuts across full face which is pretty deep for jointing.
> 
> - marcb


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