# Electric CSM



## cgarman (Sep 14, 2010)

I had a thought a while back, and wanted to see if anyone else had been thinking along the same lines. I'm toying with the idea of using a woodworking router as a power source for a chain saw mill. So far, I successfully mounted a 3/8" rim sprocket onto a slot cutting bit in place of the actual three-wing cutter. Once I got to this point, I got scared, and didn't try to turn it on.

My thinking is that the larger milling saws seem to be 8-9 hp. For $300, I can get a 3.25 hp router. I can easily (well, not too easily) buy tow, and mount one to each end of the GB mill, and run them at the same time. I could even run them through a router speed controller to adjust chain speed vs. torque.

I don't need a ton of portability, since I'm milling logs in my driveway. The advantage of electric is that I could remove some complications in keeping a CS tuned up and running perfectly. No gas to buy, so mixing, no carb adjustments, just an extension cord.

Anyone out there ever tried it?


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## discounthunter (Sep 14, 2010)

not enough torque. plus 3 hp is about a 50-60cc saw range,alittle on the small side to do much milling.


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## BobL (Sep 14, 2010)

discounthunter said:


> not enough torque. plus 3 hp is about a 50-60cc saw range,alittle on the small side to do much milling.



It's not just HP that matters. Most electric motors have all of their torque at low RPM whereas to cut under load some higher RPM torque is needed. So using a 3HP electric is more like using a 35cc CS and it will just overheat the router and unless it has a thermal cutout switch it will just burn out. Also cheaper router bearings are probably not able to take the constant side load that would be imposed by the tension generated between a sprocket and a cutting chain.

It would also be interesting to see what happens to regular chain at 20,000 rpm


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## mtngun (Sep 14, 2010)

Doesn't logosol offer an electric power option for one of their CSM's ?

Why pay $300 for a router when you can get a used or surplus 5hp 3PH motor for less than that ? Power it with a vectorless inverter from 1PH 240V. It should do the job (3ph electric motor power ratings are pretty accurate, gas engine ratings not so much, so 5hp electric should be equivalent to at least 7hp gas).

RPM's will be the problem. Assuming a 3600 rpm motor, you'll need some kind of gearing to bump the RPM's up.

Or then again, maybe do like the 4-stroke slabbing mills and run skip chain with super aggressive rakers, and slog through at 3600 rpm ? Anyone know what kind of chain speed the slabbing mills run ?


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## BlueRidgeMark (Sep 14, 2010)

If you were talking about using a 3 hp appliance or pump motor, I'd say go for it.

A router?


You'll fry it.


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## Sawyer Rob (Sep 14, 2010)

cgarman said:


> I had a thought a while back, and wanted to see if anyone else had been thinking along the same lines. I'm toying with the idea of using a woodworking router as a power source for a chain saw mill. So far, I successfully mounted a 3/8" rim sprocket onto a slot cutting bit in place of the actual three-wing cutter. Once I got to this point, I got scared, and didn't try to turn it on.
> 
> My thinking is that the larger milling saws seem to be 8-9 hp. For $300, I can get a 3.25 hp router. I can easily (well, not too easily) buy tow, and mount one to each end of the GB mill, and run them at the same time. I could even run them through a router speed controller to adjust chain speed vs. torque.
> 
> ...



Think about this... "With all the losses", it takes 10 amps to make one hp on 120V. No matter how you figure it, this will end up being VERY close EVERY time, so how many amps does that router draw? Look at the name plate, i bet it's 15 amps or less!

3hp = 30 amps, how do you pull that through a 20 amp breaker? That's what most homes have, or even worse many have 15 amp breakers!

Rob


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## huskyhank (Sep 14, 2010)

I think mtngun is close on this.

You could even skip the 3 phase motor and VFD and just buy a 5 hp single phase motor. The 3 phase motor will be cheap but having to buy a VFD to drive it defeats the cheapness or the motor. You can get a 5HP single phase motor that runs on 220V 30A. If you get a 3450 rpm motor gearing it to double speed (6900 rpm) at the chain sprocket will be close to normal chainsaw chain speed. Gearing it also lets you make a heavy duty spindle for the chain sprocket which I think you'll want for longevity rather than running it off the motor shaft.


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## mtngun (Sep 14, 2010)

VFD's are affordable these days, I think around $300 for 5hp. Plus the VFD has built in controls, without a VFD you'd have to supply a starter.

3ph motors have more torque and last much longer than single phase. They are usually cheaper than single phase, too, if you scrounge CL/ebay/surplus/rewind shops.

You could use the VFD to overspeed the motor, maybe take it up to 5000 rpm using the VFD alone -- although you'd be working the motor pretty hard, and I dunno if it would tolerate it for long. 

The problem with a VFD to convert single phase to 3 phase is that you are limited to about 5hp -- not sure if 5hp is going to do the job ?

Looks like Logosol uses a 3PH motor to run picco/lo-pro chain at 74 ft/sec. They don't state the HP, but judging by the 30 amp fuse, I'd guess 10 HP.






So it might be a reach to build an electric chainsaw mill that runs on domestic single phase power.

On the other hand, a 5 hp electric motor would be plenty to drive a small bandmill. Problem solved.


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