Horsepower on a band blade

Randy88 · January 18, 2017, 07:21:05 AM

Can anyone shed some light on just how much horsepower a band blade can take and how much is overkill and no gain in speed of sawing?

I've been told by a few band blade sales people a 1.25 wide band that not much if anything is gained in cutting speed with anything over 25 hp and to go to 1.5 inch wide bands is about 30 hp?

The reason I'm asking is then why do companies selling band saw mills put 35-50 hp diesels on their mills.

The next question is, I stumbled across a homemade mill with 1.5 inch wide bands and it runs a four cylinder diesel engine putting out 135 hp, I have not seen it in person, but been told the builder has passed away and nobody now knows much about it, not even how to run it really and I got to thinking, just how much overkill in this mill and can any band that width take or utilize anywhere near that hp and in the end, what good is it? I know everyone wants power and to never slow down, but I'm having a hard time trying to figure out how much power is necessary and how much is overkill on a band mill? I understand torque gained with a diesel and not losing engine or blade speed in hard knots or tough to saw material, but when does it become overkill?

bandmiller2 · January 18, 2017, 07:39:02 AM

Home built mills, for the most part, use whatever the builder has in stock. If that engine was belted up to run at a modest speed below its max HP range it wouldn't be too bad. I don't know how much HP you can pull a band with but I think what you were told is quite close. Over a certain point you will start stretching the bands in their gullets and their useful life will be compromised. Horse power sells, and some buyers are fixated on it. Frank C.

ladylake · January 18, 2017, 07:43:03 AM

My mill came with a 27hp Kohlor with 1 1/4 bands, way underpowered in wide cuts in tough wood. I put a 29 hp diesel with 10 more footpounds of torque, seems like it cuts twice as fast in the hard wide cuts and with a good blade it will make the engine smoke and still cut straight. Steve

Randy88 · January 18, 2017, 08:10:33 AM

I've run a lot of equipment over the years and torque is what gets the job done and why I don't really understand wanting a gas engine on much of anything your going to work or lug like a bandsaw, either a blade or band mill.

But there does come a time when the excess hp does more damage than good over the long run is my thinking, I'm just trying to figure out how much overkill this mill has built into it or if it originally had much wider bands on it and has been changed to narrower bands since the owner passed away in order to try to sell it is the only thing that comes to mind??

With the hp and extra torque of this engine, I'd think it would literally tear the bands apart upon start up or shortly there after, the torque alone would rip them apart if you'd feed the head even a fraction too fast is my thoughts, anyone thinking the same thing or am I completely wrong?? If I understood the seller right and saw it correctly in the pictures, it has six drive belts from the engine pulley to the band drive wheel, zero slip ever and I also understand it runs at about 2000 engine rpm or peak torque for that engine.

If it wouldn't be over a 1000 miles away I'd go see it in person just to satisfy my curiosity.

dboyt · January 18, 2017, 09:02:14 AM

Horsepower is subject to the law of diminishing returns. That engine may have been adapted from an old circle mill, and could pull a 5" or wider band blade for high production. Getting the blade through the wood is just part of the process. I'd take a 30 hp motor with good log handling and offbearing over 135 hp where I'd have to muscle the wood around. Also, how many people will be working the mill? An engine that size would almost certainly be stationary head rig with the log moving through the band. Is it horizontal or vertical? What size band wheels? Maximum width of cut?

Randy88 · January 18, 2017, 10:46:17 AM

No its not a stationary head, no the log doesn't move, its an upsized standard looking traveling head horizontal bandmill, on a huge chassis, with the engine mounted on the four post head rig that travels and a hydraulic pump mounted off the engine and all the controls down on the tongue with a seat and all the hydraulic controls at deck level, with a hose carrier somewhat like the older timber harvester mills had and some of the newer cooks or woodmizers. just about four times larger is all, mounted on a tandem axle chassis.

As for production, nobody seems to know, what got me is I was told they had 1.5 inch bands on the mill. I was told the maximum width of cut on the head was 30 inches and again was told, not seem myself, but 26 inch band wheels.

It's supposed to be all hydraulic for functions, again not seen the mill to verify that.

york · January 18, 2017, 11:29:19 AM

I,would like to see this mill.....

Darrel · January 18, 2017, 12:15:39 PM

It is my understanding the most limiting factor in the speed of cutting with the narrow band is the size of the gullet. With the narrow band with a 7/8" pitch the gullet fills with sawdust and speed of cut is thus limited. On the other extreme, an 8" wide band with a 5" pitch has a gullet that can carry much more sawdust and of course use more horse power.

Joe Hillmann · January 18, 2017, 01:09:39 PM

My homemade mill runs on trailer tires and the limiting factor on mine is usually blade tension. If I push the blade through the log enough to bog the engine down the blade often starts to wonder and I am pretty sure the it is the lack of tension that is causing it.

Ljohnsaw · January 18, 2017, 04:54:03 PM

Quote from: Joe Hillmann on January 18, 2017, 01:09:39 PM
My homemade mill runs on trailer tires and the limiting factor on mine is usually blade tension. If I push the blade through the log enough to bog the engine down the blade often starts to wonder and I am pretty sure the it is the lack of tension that is causing it.

On my tire-mill with 1¼" blades and an 18hp engine, if I push too hard (really hard!) with a sharp blade, it just bogs the engine. On a dull(er) blade, it wanders. As Darrel pointed out, the gullets could be a factor. Pushing to fast, they fill/pack and cause the blade to do odd things.

DPatton · January 18, 2017, 08:47:56 PM

There was a post a while back by wfcjr that touched on this topic and had some well experienced responses that followed . I am a relatively rookie owner of a TK 1600 mill that uses 1.25" blades and is equipped with a 27 hp gas engine. At my experience level I felt that my mill has an adequate power plant to cut what I do on a regular basis. However if you check out that post you will find that Ladylake ( who is a much more experienced owner than I) had some very good input on horsepower capabilities of 1.25" and 1.50" blades. You should check it out.

barbender · January 18, 2017, 09:53:55 PM

My WM has a 40 hp diesel, and I do feel it is hard to use that engine to it's potential with narrow bands. Also, on mine transmitting the power through the drive belt without slippage is a challenge.

4x4American · January 18, 2017, 10:09:56 PM

I've also been curious on this subject. Baker offers their bandmills with 2" or 1.5" I believe, maybe a 3rd option too, but my thought is why do they offer the same mill/hp with 1.5" vs 2" and what are the losses/gains. If it's the same mill besides the bandwheels, are you really gaining much if the 1.5" does the same thing; is it worth the added expenses of bigger bandwheels and blades?

JustinW_NZ · January 19, 2017, 12:27:29 AM

Im running the 37hp diesel on my WM and do a lot of tough wide stuff.
It also is a super mill, so oversize alternator if that drags a little power?

Would I swap it for a 25hp electric with full on torque? - heck yes!
135 sounds a bit overkill however?

Cheers
Justin

4x4American · January 19, 2017, 06:18:54 AM

No such thing as overkill smiley_deadheader alligator

sandsawmill14 · January 19, 2017, 06:44:28 AM

i cant say about the baker mills but there is a world of difference between the 1 1/2 and the 2" bands and most likely they run the same band wheels at least thats the way our brewco resaw is made it has a 50hp electric motor on it

4x4American · January 19, 2017, 06:58:25 PM

Good to know Sands..Been running that S&W?

esteadle · January 19, 2017, 07:54:20 PM

I think with more HP, it comes down to being able to pull the blade through the wood when it is dull. The more HP you have, the longer you can run your blade into "dull" before you need to change it. A proper, sharp blade will cut with almost any HP. A dull blade will bog and stall with too low HP. A high HP engine can pull a dull blade through, and can keep up the feed rate while doing that.

But you really don't want to saw with a dull blade if you can help it. Feed rate becomes more "touchy" because the HP is limited and you get to the top of the engine's power range more quickly as you cut. Your engine runs hotter, you use more fuel, and you put more stress in the gullet, which fatigues the blade quicker and shorten it's life. A sharp blade is the most important part on any cutting tool.

4x4American · January 19, 2017, 08:53:58 PM

Even if you have the power to pull a dull blade, the blade isn't gonna wanna cut very accurately, no?

redprospector · January 19, 2017, 09:02:36 PM

Quote from: esteadle on January 19, 2017, 07:54:20 PM
I think with more HP, it comes down to being able to pull the blade through the wood when it is dull. The more HP you have, the longer you can run your blade into "dull" before you need to change it. A proper, sharp blade will cut with almost any HP. A dull blade will bog and stall with too low HP. A high HP engine can pull a dull blade through, and can keep up the feed rate while doing that.

But you really don't want to saw with a dull blade if you can help it. Feed rate becomes more "touchy" because the HP is limited and you get to the top of the engine's power range more quickly as you cut. Your engine runs hotter, you use more fuel, and you put more stress in the gullet, which fatigues the blade quicker and shorten it's life. A sharp blade is the most important part on any cutting tool.

Not to mention the fact that you probably don't want to turn out a substandard product.
I've got a 1600cc VW engine on one of my mills, and it will keep pulling a dull 1 1/2" band through the waves right up until it breaks.

sandsawmill14 · January 19, 2017, 09:35:37 PM

4x4 nope we are not running the s&w we are still cut off on ties and nobody can sell mixed wood lumber right now so i just sawing a little with the b20 and enjoying the time off

( but the bankers are not enjoying much as i am :

:D :D :D )

and the dull bands will not cut flat no matter the hp ;)

4x4American · January 19, 2017, 09:53:39 PM

See anytime I think about getting more production, I worry about getting cut off or cut down. I'm at 1 load (200-260 ties) per month right now for ties, which works out fine for me anyways. I also think, gee, that's alot of lumber I'm gonna haven to handle. Sawing ties by myself right now keeps me scrambling to keep up lol.

Those dern bill collectors, when they call, tell them that you put all your bills in a hat and pick 3, and your bill wasn't picked, sorry, better luck next month! lol

sandsawmill14 · January 19, 2017, 11:56:16 PM

i just ask them if they wanna go in the sawmill business :D :D :D :D

far as quotas we need to be at a load a week to be able to run everything then you still have a load or load and a 1/2 of lumber to do something with :-\

it will turn around one of these days though this is my 3rd time to go through this in the last 20 or so years :

it always comes back and i will be ready when it does ;D

4x4 just remember if you double your production you will triple your headaches

:D :D :D
far as my production i cut 20-25 ties a day by myself with the b20 its a hard day but thats sawmilling