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Ideal torque values for wide throat bandsaw mill?

Started by dcg4403, April 11, 2014, 01:22:32 PM

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dcg4403

So I've seen quite a bit of information about HP ratings for mills but little about torque ratings.   I feel torque is a more important performance value than HP.    I'm building a bandsaw mill with up to a 52" wide throat.   I'm using Cook 30" bandwheels.   This is not a high production mill where my feed rates are critical.   I'm more concerned about cut quality in hardwoods like pecan and hickory.   I plan on using a 2" wide band.   

I'm ready to purchase my motor but need some input regarding HP and Torque. 

I leaning toward purchasing a used 3 cylinder diesel motor.   HP is rated at 20 HP at 1500rpm  and 30HP at 3200 RPM.   Torque is pretty constant at 55 ft/lbs from 1500-3200 RPM.   Nice & compact, weighs 400 lbs. 

The other option is a 4 cylinder Yanmar diesel which roughly puts out ~40HP & 85 ft/lbs.  It is much larger and weighs 750 lbs. 

Can I get advice on determining the ideal torque/hp numbers given my application?   I know typically bigger is better but I'm trying to avoid an excessively heavy carriage. 

Devin Ginther, BSE, PMP, MBA
devin@refinedelements.com
Texas Urban Sawmill LLC, Owner
Refined Elements LLC, Owner

kelLOGg

Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

Magicman

Welcome to the Forestry Forum, dcg4403.

I am not in any way qualified to discuss your HP question, but with those 30" bandwheels and 2" blades, I wonder if the 40HP is large enough??  As kelLOGg mentioned, that is a big sawmill.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

scrout

DCG,

HP and torque are usually a curve on a graph over the operating RPM of the engine.
What you want is a high torque at the RPM you want to operate.
I think almost all diesel engines make for a nice sawmill power source.
Acknowledging that there is no such thing as too much power, at 1500 rpm the 3 cylinder will run all day on the smell of an oily rag.
With that large a setup I would assume 40hp would be the way to go.
Additionally, any gear ratio in your drive pulleys will multiply the torque.
My wheels run at 1000 rpm, my motor at 3000 rpm, so I get a 3x torque multiplier right there, but I have a gas engine so it needs to run up there to get the power.

Nomad

     Yanmar stands in a class by itself for small diesel engines, in my opinion.  I'd go with that.  But the width you're wanting to cut...  I dunno about that.  I'd go with the Yanmar.  You need enough power to keep the band moving in wood that wide.
Buying a hammer doesn't make you a carpenter
WoodMizer LT50HDD51-WR
Lucas DSM23-19

Den-Den

By adjusting the band speed so that you load (but not bog down the engine), either of those engines could do the job.  I would suggest planning the pulley ratios carefully and allowing for future changes of that ratio after you use the machine. 
If you are using that width capability very often, get all the hp that you can afford and you won't need as much patience.
You may think that you can or may think you can't; either way, you are right.

5quarter

DCG...welcome. Sounds like you're building an AC-52. I'm with Bob, call Tim Cook and pick his brain. He's already built that mill and caould probably give some sage advice. Put up a few pics of what you have so far. sounds like a real interesting build.
What is this leisure time of which you speak?
Blue Harbor Refinishing

dcg4403

Thanks for all the input.    I have spoke to Premium Wheels and they suggested a minimum of 30HP but more ideally 40-50HP.   They preferred a 3" wide band for a mill operating at 8 hrs/day but said 2" would be fine considering that my mill is operating only part-time & feed speed is not my 1st priority.  Premium build wheels for some of the largest mills in the world and commonly replace the cheaper wheels found on the popular portable mills.   I will also give Cooks a call as recommended. 

One thing for me to consider is that I will very rarely be cutting into 40"+ logs.   Normal size is 24-32".  I might cut 6-8 48" monster logs a year.   I do like that little 3 cyl diesel but the Yanmar is no more expensive for me....just a lot heavier & larger. 

What's funny to me is that I've run a very inexpensive Oscar 52 with a 24 HP honda on it.   It cut hardwoods will few problems on 40"+ logs.  I was feeding it at a very slow walk but I wasn't complaining.   I can see a more powerful saw running at rates 4-5X faster. 


Devin Ginther, BSE, PMP, MBA
devin@refinedelements.com
Texas Urban Sawmill LLC, Owner
Refined Elements LLC, Owner

dcg4403

Considering future add-ons and hydraulics......the Yanmar 4 cyl is what I'm going to get.    Hopefully I will start my build in a few weeks and start a fresh thread. 
Devin Ginther, BSE, PMP, MBA
devin@refinedelements.com
Texas Urban Sawmill LLC, Owner
Refined Elements LLC, Owner

Magicman

Quote from: dcg4403 on April 11, 2014, 01:22:32 PMI leaning toward purchasing a used 3 cylinder diesel motor.   HP is rated at 20 HP at 1500rpm  and 30HP at 3200 RPM.   Torque is pretty constant at 55 ft/lbs from 1500-3200 RPM.   Nice & compact, weighs 400 lbs. 
With the research that you have done I am curious about this statement that you made yesterday??   ???
Quote from: dcg4403 on April 12, 2014, 10:56:43 AM
Considering future add-ons and hydraulics......the Yanmar 4 cyl is what I'm going to get.   
And then today.   Did we influence your decision?

Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

ladylake

 4 cylinder for sure cutting that wide takes power,  also even if a motor keeps it's torque down to 1500 RPM and it's peak HP is a 3000 Rpm with a band mill you cant lug it down that much, you need to maintain the 3000 rpm band speed to cut good.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

backwoods sawyer

On a four post hydraulic mill like the Cooks weight is not as much of an issue as it is on the Woodmizer and the added HP will let you run hydraulics off it as well. It also takes more to get the larger wheels up to speed. If cost is not an issue the larger HP would be the way to go.
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

dcg4403

Update.  I went ahead and purchased a Kubota V2203 4 cyl which is a more powerful diesel than then Yanmar I was looking it.    Two different diesel experts recommended it overall compared to Yanmar.  Mainly because they said any tractor or heavy equipment dealer / repair shop will have parts immediately available and parts cost about 50% less.   Plus, it is rated for more HP and torque and cost me less.   I paid $1400 shipped for a used one with a warranty and all bolt on extras.   

I actually called Cooks, but I guess I needed to speak with one of the Cook's brothers.  If I recall correctly, I spoke with Billy, who was not very helpful whatsoever.   He wasn't rude or anything like that.   He was attempting to be helpful but simply wasn't technically knowledgeable when I asked detailed questions.   I'm an engineer and wanted very technical explanations.   I was simply told they use 26" wheels on their saws and I'd be fine with any size.   

I'm going with 30" wheels as I good compromise.  Fairly cost effective compared to 36" wheels.  Cooks has fairly decent pricing on them compared to Premier.  Love to have Premier wheels but they are over 2x the cost of the cooks and are probably overkill given my usage.   I must say that Premier has expert knowledge about large commercial mills.   They simply wheels for some very expensive commercial mills.  Very impressive knowledge.   

Anyway, I think that settles this thread.  I will start a new thread of my build up and try to give as much info as possible to others.   

Devin Ginther, BSE, PMP, MBA
devin@refinedelements.com
Texas Urban Sawmill LLC, Owner
Refined Elements LLC, Owner

Ga Mtn Man

Looks like a nice engine at a good price.  Looking forward to following your build.
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

backwoods sawyer

The local Kubota tracktor shop can not get parts for the generator models I have to go thru the kubota shop up north that sales generators :(
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

thecfarm

Both Kubota dealers I had,I had to wait a week for parts.  ::) Sometimes 2 weeks.  ???   >:(
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

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