M-type belts: Are 2 enough for a 3HP motor?

[Allan Speers]

I have an 8" jointer with a 1.5 HP 1-ph motor.
I will be adding a helical head soon, and I know that that requires a bit more power than a knife head.

Yes, I realize that 1.5 HP isn't horribly anemic for an 8" jointer, but besides the helical head issue, (Which I'm adding to lower the noise as I have a neighbor from hell) I will be mostly face-jointing wide boards. I have a HUGE amount to process, and much of it is Hard Maple, so...

OK, so this is just me weighing my options:
-----------------

I'm thinking of getting a used 3 HP / 3 ph motor, and adding a VFD. My question concerns the pulleys & belts:

The current setup uses dual groove pulleys with M-style V-belts, which are 3/8" across.
I know that many 3 HP machines have used dual 4-L belts, which are 1/2" wide.
However, there is no room in the base opening to clear wider belts, and the cutterhead shaft might be a hair short for a wider pulley. So, I'd prefer to stay with the M-type belts & original pulleys. (less money to spend, as well.)

SO:

Q: Can two M-type belts handle a 3 HP motor, if it’s not being heavily stressed?

[David Kumm]

Aren't M belts just metric sized? L belts are fractional HP so an M will transfer power at least as well if not better. I wouldn't worry about swapping them. I'm not sure an 8" jointer needs more hp. The machine is engineered for the stress of cutting at a rate the 1.5 hp will handle. Increasing the motor might add to the depth of cut but will also stress the bearings, arbor, and machine. Dave

[Allan Speers]

Aren't M belts just metric sized?

Are they? Hmmm, maybe so. If so, maybe a 1/2" belt will ride in the same pully, just a little bit higher.
I'm going to check that tomorrow. (Although as you say, it might not matter.)

The machine is engineered for the stress of cutting at a rate the 1.5 hp will handle. Increasing the motor might add to the depth of cut but will also stress the bearings, arbor, and machine. Dave

Certainly a good thought but -
The bearings & arbor will be replaced along with the cutterhead, so no worries there.
I suppose one MIGHT be concerned about the bearing beds, but I can't imagine that really being a problem.

[Malcolm McLeod]

I'll say away from discussion of whether you 'need' more power, but as to belt sizing... Years ago I had a shelf full of catalogs with belt/sheave sizing guides. Now with access to ALL the world's info a keystroke away, a quick search & I can't find even ONE.

A call to your local v-belt/gear/bearing supplier (MotionIndustries/Grainger/McMaster?) will probably get you properly informed. As I recall you'll need motor rpm, sheave diameters (both :: and so speed ratio >> cutter rpm), and shafts ctr-to-ctr distance. They should be able too tell you the number of belts required for a given power.

[Bill Dufour]

Depends on the size of the smaller pulley and the percentage of wrap. I assume about 50% wrap? I would think a helical head would take less power since it never takes a full width cut. If you are really worried you could convert to serpentine belts which can transmit a lot of power in not much width.
Bil lD

[Jacob Reverb]

Maybe this will help:

https://www.bearingsandindustrialsup...belt_drive.pdf

[Mike Kees]

Allan before you rush off and buy a different motor,try that one out first. I had a Delta 37-315 jointer (8") that I bought used with a one horse motor. That machine was used to flatten the face of about 600-700 board feet of Birch shortly after I bought it,it handled the job fine and I never upgraded it.

[Tom M King]

Belts thicker than the fractional horsepower belts, such as automotive belts, will add vibration to the machine. I don't know what an M is, but you don't want stiffer, with larger bumps where the belt is put together, than the L's.

[Rich Aldrich]

I have a Jet 6” jointer that had straight knives. I swapped out the cutter head to a Byrd Shelix about 2 years ago. It has a 1 HP motor and one belt. It works fine. I would think the 1-1/2 hp motor would be fine. The shelix head is a little smaller and does not take off as much at maximum depth. Most of the time one isn’t taking a big cut with a jointer so I question the need for a larger motor. If it were me, I would try it with the existing drive arrangements and go from there.l

[Tom Bender]

As Bill says, diameter of the smaller pulley determines torque capacity. So if you need more you might be able to increase the diameter of both. And the efficiency of the drive is better if the belt doesn't have to bend around a small pulley and straighten again 2000 times a minute.

Also, a more massive belt will absorb more power making heat instead of wood chips.

[Joseph Montroy]

I have a PM60 with a Byrd head and a 1.5hp motor. No issues with power at all and I use a lot of qswo and hard maple. You'll love the new head!!

[Rod Sheridan]

Hi, you will be fine with the existing motor and belts.

I wouldn’t change them.

Regards, Rod

[Allan Speers]

Thanks, guys.