# what rpm motor for a jointer?

• posted on April 9, 2006, 2:02 pm

I have an old jointer I need to set up today and was wondering what rpm motor I should use?
Thanks,
Craig
www.vintagetrailersforsale.com
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• posted on April 9, 2006, 9:58 pm
cm wrote:

you will need to get the rpm of the cutter shaft to about 4500 RPM.
You adjust the speed by selecting the correct sized pulleys. For example if you use a 1750 RPM motor, divide 4500 by 1750 and get 2.6. That means the diameter of the pulley on the motor must be 2.6 times the diameter of the pulley on the cutter shaft to achieve a 4500 rpm. If you use a 3500 rpm motor then the motor pulley should be 1.3 times the diameter of the cutter pulley.
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• posted on April 10, 2006, 12:18 am
Thanks George!
Craig

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• posted on April 10, 2006, 2:52 am
Thanks George - right on point. Exactly what we need to know. 4500RPM And the Math! Good job!

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• posted on April 10, 2006, 9:01 pm
On Mon, 10 Apr 2006 02:52:21 GMT, "Gooey TARBALLS"

Yeah, and then remember. jointers are sometimes rated by cuts per min, so you need to multiply by the number of knives. Just thought I'd add this critically important info

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• posted on April 10, 2006, 10:16 am

A little more information would be necessary to answer your question. Besides, with the right pulley sizes, you could use any RPM motor. The correct approach is determining the cutterhead speed and then calculating pulley sizes to match a standard RPM motor. To figure out the cutterhead RPM you need to know the effective diameter of the circle the knives make as they spin, the number of knives, then you can (I imagine you can anyway) probably google recommended surface speed for that combination and start working backwards to figure out pulley sizes & RPMs.
OR, you could just look at a similarly sized and equipped working jointer and take it from there.
--

Larry Wasserman Baltimore, Maryland
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• posted on April 10, 2006, 4:17 pm
Is there an optimum speed?
Would this change depending upon the number of blades"
Or is the speed determined by the number of CUTS PER MINUTE?
While we're on the subject, would three blades be the max number of blades used?
Are there other cutter head types (beside blades) in use on jointers?

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• posted on April 10, 2006, 5:49 pm
cm wrote:

you got some good answers to your motor speed question. what hasn't been addressed is motor horsepower. pullies will get you to the right cutterhead speed, but you need enough hp to drive it. you don't say what size your jointer is, but for comparison I have a 2 hp motor on my 8" jointer and that seems about right.