simple electric chainsaw mill...crazy?

mikeb1079 · Jan 31, 2010

sooo, i've got some logs sitting around the house and i'd like to mill them this spring. there is no way i'm gonna be able to bust out the old 066 and let er rip with all the neighbors homes so close to ours. :chainsaw:

this got me to thinking about taking an old 5hp 3750 rp electric motor i've got laying around and somehow welding/attaching/jerry rigging the arbor of the motor to a sprocket which drives the chain around a standard bar. i don't know if i'd try to mount it on a rail carriage like a bandsaw mill, i haven't thought that far ahead yet. i know 5 hp seems small, but i'm not gonna be milling 40" diameter hickory here, just some smaller logs i've brought home from various places. plus, maybe i could use lo pro chain. quiet is the goal.
thoughts? :givebeer:

edit: what about using an actual chainsaw clutch to drive the sprocket. the clutch could be threaded on a rod which is driven by a pulley attached to the electric motor?

BobL · Feb 1, 2010

mikeb1079 said:
sooo, i've got some logs sitting around the house and i'd like to mill them this spring. there is no way i'm gonna be able to bust out the old 066 and let er rip with all the neighbors homes so close to ours. this got me to thinking about taking an old 5hp 3750 rp electric motor i've got laying around and somehow welding/attaching/jerry rigging the arbor of the motor to a sprocket which drives the chain around a standard bar. i don't know if i'd try to mount it on a rail carriage like a bandsaw mill, i haven't thought that far ahead yet. i know 5 hp seems small, but i'm not gonna be milling 40" diameter hickory here, just some smaller logs i've brought home from various places. plus, maybe i could use lo pro chain. quiet is the goal.
thoughts?

edit: what about using an actual chainsaw clutch to drive the sprocket. the clutch could be threaded on a rod which is driven by a pulley attached to the electric motor?

3750 rpm is not going to get you very high chain speed so your milling speed will be kinda slow. You could of course up the sprocket size to something like a 21 pin but that means the 5HP will be lucky to cut 12" logs. You will need around 12 HP electric wise to be competitive with your 066.

gemniii · Feb 1, 2010

It seems that even in the smaller bandsaw mills, which require less power, 5hp does not cut it.

mikeb1079 · Feb 1, 2010

underpowered

hmmm....i had thought that perhaps that was a bit underpowered. i can always get a bigger motor. i need to keep scheming on this. i think a stationary electric chainsaw mill in my driveway is the way to go. hmmm...

wdchuck · Feb 1, 2010

There are folks that have used an electric chainsaw to mill with. The youtube has some videos too.

woodsrunner · Feb 1, 2010

I love it when people think outside the box! Sic 'em boy!

Scott

mikeb1079 · Feb 1, 2010

I love it when people think outside the box! Sic 'em boy!

ha! indeed my friend, indeed. i've wanted to build a bandsaw mill for awhile now, but i was confronted by how to deal with the noise issue. i figured i'd have to load up a trailer of logs and go out into the country so i wouldn't bother anyone. but yesterday when i was scheming (one of my favorite pastimes) the lightbulb went on and i thought: "electricity!".
so here's my new idea:
pick up a 15-20hp electric motor, three phase. then i pick up a 25-30 hp electric motor to use as an idler motor, which works as my poor mans rotary phase converter. :chainsawguy: i've just done this on a smaller scale to power an industrial conveyer belt with a 3 phase motor and it works quite well, you just pull start the idler motor and then run it off single phase 220.
the local university surplus just had a 20hp three phase motor for 75 bucks, so it shouldn't be too bad fiscally for the motors.
i would certainly think that 15-20hp should be sufficient to power this mill.

to answer the chain speed problem, couldn't i just make the pulley on the motor 3 times the diameter of the drive pulley, thus tripling the 3500rpm of the motor?

i'll have to learn how to scan drawings on the comp to run all this by you guys.

:cheers:

Sawyer Rob · Feb 1, 2010

mikeb1079 said:
ha! indeed my friend, indeed. i've wanted to build a bandsaw mill for awhile now, but i was confronted by how to deal with the noise issue. i figured i'd have to load up a trailer of logs and go out into the country so i wouldn't bother anyone. but yesterday when i was scheming (one of my favorite pastimes) the lightbulb went on and i thought: "electricity!".
so here's my new idea:
pick up a 15-20hp electric motor, three phase. then i pick up a 25-30 hp electric motor to use as an idler motor, which works as my poor mans rotary phase converter. :chainsawguy: i've just done this on a smaller scale to power an industrial conveyer belt with a 3 phase motor and it works quite well, you just pull start the idler motor and then run it off single phase 220.
the local university surplus just had a 20hp three phase motor for 75 bucks, so it shouldn't be too bad fiscally for the motors.
i would certainly think that 15-20hp should be sufficient to power this mill.

to answer the chain speed problem, couldn't i just make the pulley on the motor 3 times the diameter of the drive pulley, thus tripling the 3500rpm of the motor?

i'll have to learn how to scan drawings on the comp to run all this by you guys.

It takes a GOB of electricity to run a 20hp RPC and also the 20hp motor it's running. Do you have that much power available? More importantly, you can't run a 20hp motor on a 20hp RPC and get much of anything out of the motor. You have losses going through the RPC.

I have a RFC to run one of my drill presses, lathe ect., and in practice you loose quite a bit of hp.

Rob

mikeb1079 · Feb 1, 2010

It takes a GOB of electricity to run a 20hp RPC and also the 20hp motor it's running. Do you have that much power available?

no, i've just done some quick calculations based on what i've observed using my rfc and it looks like i was a tad ambitious with my guesstimations. but i think if perhaps i use a 10hp motor with a 15 hp idler i may need around 100 amps. this could be do able. i'll keep yall posted. :biggrinbounce2:

Sawyer Rob · Feb 1, 2010

mikeb1079 said:
no, i've just done some quick calculations based on what i've observed using my rfc and it looks like i was a tad ambitious with my guesstimations. but i think if perhaps i use a 10hp motor with a 15 hp idler i may need around 100 amps. this could be do able. i'll keep yall posted.

I think it will take more than 100... You may just as well buy a decent 7.5hp single phase, you'll end up in close to the same place anyway...

This is why 99.9% of the folks just end up with a gas motor, and with a good muffler thay can be plenty quiet..

Rob

BigE · Feb 1, 2010

mikeb1079 said:
so here's my new idea:
pick up a 15-20hp electric motor, three phase. then i pick up a 25-30 hp electric motor to use as an idler motor, which works as my poor mans rotary phase converter.

OK, so what am I missing here?

Why not just run it off the 25-30HP motor? (assuming that isn't 3ph).

Running a bandsaw is going to take a whole lot less juice vs. a chainsaw, if you are wanting to go the electric route.

Sawyer Rob · Feb 1, 2010

BigE said:
OK, so what am I missing here?

Why not just run it off the 25-30HP motor? (assuming that isn't 3ph).

Running a bandsaw is going to take a whole lot less juice vs. a chainsaw, if you are wanting to go the electric route.

I'm not clear as to your question, are you asking why not run it off a 25-30 single phase motor??? Other than a writenpole motor there is NO single phase motor that big, and "really" a writenpole isn't a single phase either, but it's made to run on single phase.

BTW, "IF" there was a 30hp single phase, it would take close to 300 amps to run it!!

Rob

isaaccarlson · Feb 1, 2010

You can quiet a chainsaw down quite a bit if you put a

good can muffler on it. It does not have to be big or restricting, it just has to catch some of the noise. I have seen some pretty quiet exhaust systems that are not choked off.

jdrum · Feb 2, 2010

mike go for the 3 ph. buy rope starting or pony motor the idler, there is hardly any startup amperage spike. and with no load it will only draw 10 or 12 amps. the 10 or 15 hp motor on the mill should be run to a jackshaft with chain sprocket and pulley. i myself would use a spring loaded idler and desingage the belt, creating a no load condition on the mill motor, then the startup spike amperage. is lower. check the fla on the motor plate. thats the amount of amps drawn under full load. you should be able to ron that setup on a 50 or 60 amp breaker.

rob
you said, I have a RFC to run one of my drill presses, lathe ect., and in practice you loose quite a bit of hp.

Rob

may i ask do you have rotary phase converters on your machines or are they static converters. ( do they have idler motors or are they just a box of caps.and contactors.) motors started with static converters only develope 60 to70% of there rated power. motors started with rotary phase converters ( idlers) devlope 90%+ of there rated hp. this is accepted knowledge, even the rpc manufacturers admit this.

jim

rarefish383 · Feb 2, 2010

Long ago I saw a picture of what looked like an old Disston 2 man saw transmission and bar rigged to an electric motor. It was being used as a chop saw cutting off the ends of rough cut lumber. It was pretty neat, Joe.

Sawyer Rob · Feb 2, 2010

jdrum said:
mike go for the 3 ph. buy rope starting or pony motor the idler, there is hardly any startup amperage spike. and with no load it will only draw 10 or 12 amps. the 10 or 15 hp motor on the mill should be run to a jackshaft with chain sprocket and pulley. i myself would use a spring loaded idler and desingage the belt, creating a no load condition on the mill motor, then the startup spike amperage. is lower. check the fla on the motor plate. thats the amount of amps drawn under full load. you should be able to ron that setup on a 50 or 60 amp breaker.

rob
you said, I have a RFC to run one of my drill presses, lathe ect., and in practice you loose quite a bit of hp.

Rob

may i ask do you have rotary phase converters on your machines or are they static converters. ( do they have idler motors or are they just a box of caps.and contactors.) motors started with static converters only develope 60 to70% of there rated power. motors started with rotary phase converters ( idlers) devlope 90%+ of there rated hp. this is accepted knowledge, even the rpc manufacturers admit this.

jim

I have a RFC with "balanced phases" ect... It's done properly with start caps ect... The origional post was about just taking an old 20hp 3ph motor and rope starting it, NO caps to balance the phases or anything else.

I think you already know what happens when you do it this way, and then expect to pull near full capacity out of the motor and idler.

What you describe above, is a RPC like i have, properly built. There's a BIG difference between those two, and you still get losses even if it's done right.

BTW, i think the accepted power in the REAL world it closer to 80% if you want it to last.

Rob

mikeb1079 · Feb 2, 2010

electric chainsaw mill

hey guys, i should have been a little more explicit with my original post. looking back, it was a little short on info. firstly i should say that i will be using 3 phase motors. as sawyer rob pointed out, once you get close to 10hp, there really aren't many single phase motors around. plus, you can find good used 3 phase motors for cheap as a lot of places are phasing them out. :laugh:

i myself would use a spring loaded idler and desingage the belt, creating a no load condition on the mill motor, then the startup spike amperage. is lower

i agree. what i would do is to start the idler motor with no load at all. then the output of the idler motor goes to a disconnect which is your on/off switch for the saw motor. (fused and grounded of course)

have a RFC with "balanced phases" ect... It's done properly with start caps ect... The origional post was about just taking an old 20hp 3ph motor and rope starting it, NO caps to balance the phases or anything else.

I think you already know what happens when you do it this way, and then expect to pull near full capacity out of the motor and idler.

What you describe above, is a RPC like i have, properly built. There's a BIG difference between those two, and you still get losses even if it's done right.

BTW, i think the accepted power in the REAL world it closer to 80% if you want it to last.

i should have been clearer on this point. i absolutely do intend to use quality capacitors to balance the output phases of the idler motor. i agree that real world power is probably 80% of what true three phase would give you. keep in mind, there's alot of electric ranges out there that are drawing 30/40 amps per leg (220v). my electric chainsaw mill really wouldn't be drawing much more than this. i'd just have to make sure that we weren't cooking dinner and milling at the same time! :laugh:

jdrum · Feb 2, 2010

mike
you got your s=== together go for it!!!! you have DONE YOUR HOMEWORK.

jim

Can8ianTimber · Feb 2, 2010

I sure hope you go for it!!!! Although there are lots of details to take into consideration, it is not rocket science. I am currently working on a cad drawing for a electric version of a lucas style slaber.

woodsrunner · Feb 2, 2010

Innovation by everyday folks is what makes the world work. Innovation in the CSM game is just as important. Read Malloff's book and then start reading the posts here. Big strides in a relatively short time frame. The same goes for the bandsaw industry. Small portable bandsaws are a relatively new approach to cutting lumber. Especially look at BobL's innovations. Who would have thought to put a temp gauge and a tach on a saw? Those innovations really help the rest of us. Don't be discouraged by the people who say you can't do it. Just keep on thinking outside the box and you'll get there. I personally think electric power for a stationary CSM is a smart idea. I know we learned a long time ago that electric power for our deep turbine irrigation pumps made a lot more sense than diesel power units. I think all those same reasons would apply to a stationary CSM.

Scott

simple electric chainsaw mill...crazy?

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