DIY bandsaw mill question

cib · July 03, 2014, 06:28:44 PM

Hello,

long time reader first time poster. I haven't seen this particular question asked much and wanted to get some input. I'm in the early stages of building a sawmill. We have a family farm and a lot of hardwood and pine growing on it in several plots and I'd like to use this wood for a couple of barns and some cattle fencing. I've always enjoyed making things and I'm quit skilled in wood and metal working so this is a project I figured I'd start out with the intention of building my own.

I'm wanting to build a hydraulic bandsaw mill but one thing I'm curious about. Has anyone ever used a hydraulic motor to power the band itself? with gearing I can get the speed to where it needs to be and i've found several hydraulic motors that put out far more torque than a regular gas or diesel.

I know power's not free so I'll need a large power unit if I intend to run a fully hydraulic mill, meaning if I want 15HP at the band I'll need a larger motor powering the hydraulic motor. I'm just curious if anyone has tried this. I've looked at a lot of hydraulic mills on the market and most of the motor powering the band and a smaller pump that runs the log turner/loader and head drive.

Thanks for any information.

york · July 03, 2014, 06:50:52 PM

Hi and welcome,two mills come to mind-Log master and the
Serra,Montana ME 90....both these mills are HYD. driven....
With the Log Master mill only the big mills used Hyd motors to run the Band wheels.....

Joe Hillmann · July 03, 2014, 10:31:22 PM

I am not hydraulic expert but I would assume you would loose a lot of power doing it that, and most of that power would be come heat in the hydraulic fluid that you then have to cool off some how. That and if you are buying the parts new for doing a hydraulically powered saw it can add a lot of extra expense.

With that said there are probably several reasons why going with a hydraulically powered saw would have advantages in some situations.

MartyParsons · July 03, 2014, 10:47:50 PM

Hello,
is this what you are looking for? No gearing direct drive. Auto clutch even worked, motor slowed down when disengaged and the motor would speed up when engaged. This was a LT40 Super he now has a LT70 done the same way.

Marty

barbender · July 03, 2014, 11:12:47 PM

Holy smokes Marty! Is that an Amish mill, or what is the reason for that set up?

dun that · July 03, 2014, 11:40:29 PM

Interesting topic.

Im watching and waiting on more info on this one. I would like to see more pics and info on that conversion, thats definently a one of a kind conversion on that mill, do you have and more pics of it Marty. If you do thanks in advance.

cib · July 04, 2014, 12:10:11 AM

Quote from: Joe Hillmann on July 03, 2014, 10:31:22 PM
I am not hydraulic expert but I would assume you would loose a lot of power doing it that, and most of that power would be come heat in the hydraulic fluid that you then have to cool off some how. That and if you are buying the parts new for doing a hydraulically powered saw it can add a lot of extra expense.

With that said there are probably several reasons why going with a hydraulically powered saw would have advantages in some situations.

A lot depends upon the efficiency of the pump but they can be very efficient. I've got a slightly larger diesel engine I could use to drive the pump is a major reason as I could keep the head weight down and put the motor elsewhere on the mill. Not sure I want to go this route but it was a thought.

I'm likely to gear the motor to get the proper SFPM from the blade. I'd be able to control blade engagement from one location as well as move the log, load the log etc.. The hardest work the pump would have to do is power the bandsaw itself, not likely to have the loader and the head going at the same time so I could get away with a slightly smaller pump.

cib · July 04, 2014, 12:12:36 AM

Quote from: MartyParsons on July 03, 2014, 10:47:50 PM

Hello,
is this what you are looking for? No gearing direct drive. Auto clutch even worked, motor slowed down when disengaged and the motor would speed up when engaged. This was a LT40 Super he now has a LT70 done the same way.

Marty

Wouldn't have thought that would get to high enough RPM for the blade to cut properly.

Just checked and it would be more than enough. 700 RPM would put me at 4396 SFPM so yeah it could do it with a direct drive, note the calculation is done assuming 24" band wheels that I'm considering.

Ianab · July 04, 2014, 12:41:46 AM

Peterson made some some portable swingblade mills that had hydraulic powered blades. They could be hooked into the auxiliary hydraulics of a larger farm tractor (needed to be ~70 hp to supply enough oil flow) I've seen them powered by a smaller diesel mounted on the trailer that also transported the mill. Even seen one set up stationary with an electric power pack.

While you would have some losses in the system, and it would cost more if you where buying new parts (like a commercial mill manufacturer would), if you could source used components you could make it work.

Naturally the oil heating will be an issue, but a large reservoir and an oil cooler can solve that relatively easily.

Ian

bandmiller2 · July 04, 2014, 07:24:53 AM

I have a friend that built such a mill, hydraulic band drive, and it works well. As an added bonus he has a pressure gauge and can tell when the band just starts to dull. For intermittent use the power loss is of little concern, its just the cost to build that is the big restraint. Some gear type pumps can be used as motors if they have the right shaft sealing. Frank C.

StimW · July 04, 2014, 12:00:22 PM

You can buy hydraulic motors with specific set RPM.
I have an older mortar mixer that the paddle shaft runs about 36 rpm no matter how high the pump/motor rpm.
Surplus Center has good prices and selection on hydraulic components.

MartyParsons · July 04, 2014, 09:16:43 PM

Hello,
This mill Wood Mizer LT40 had way over 15000 hours before he went to the LT70. It is the same set up on the LT70. The LT40 is still working at another location in PA every day.
They have a diesel engine running the pump. The operation has a gutter cleaner, edger, planer, log deck. The engine is in another room beside the operation. As you can see in the picture it has a paragraph that has the hydraulic pipes built into it.
I know of three of these mills set up this way. The auto clutch system works amazing. When the engine is lifted that have a valve the starts the blade slow then speeds up to 5200 SFM. He could also change the flow a little to slow up the blade in frozen logs.
Sorry no more pictures.
Marty

hackberry jake · July 04, 2014, 09:45:14 PM

I saw a video of a homemade mill that used a hydraulic motor to spin the band wheels. He was using a bobcat as the hydraulic power source. Other than hooking and un hooking, it seemed like it could make a really efficent operation. One engine for all of the work being done.

cib · July 05, 2014, 11:11:17 PM

Quote from: MartyParsons on July 04, 2014, 09:16:43 PM
Hello,
This mill Wood Mizer LT40 had way over 15000 hours before he went to the LT70. It is the same set up on the LT70. The LT40 is still working at another location in PA every day.
They have a diesel engine running the pump. The operation has a gutter cleaner, edger, planer, log deck. The engine is in another room beside the operation. As you can see in the picture it has a paragraph that has the hydraulic pipes built into it.
I know of three of these mills set up this way. The auto clutch system works amazing. When the engine is lifted that have a valve the starts the blade slow then speeds up to 5200 SFM. He could also change the flow a little to slow up the blade in frozen logs.
Sorry no more pictures.
Marty

I'm going to check into pumps later next week but there are hydraulic power packs run by diesels nearby so I'm going to keep a watch out for one. I've got a nice hatz diesel engine that was a former military generator engine.

bandmiller2 · July 06, 2014, 08:31:13 AM

Cib, theirs no way to get around the power requirements for an efficient bandmill you will need in the neighborhood of 20 HP minimum, and more to drive the pump would be better. It will take serious oil volume to drive the bandwheels with the speed and power needed, not to mention keeping it cool. Belts are a much more efficient way to transfer power, and hydraulics for feed and functions. Frank C.

cib · July 06, 2014, 11:02:06 PM

Quote from: bandmiller2 on July 06, 2014, 08:31:13 AM
Cib, theirs no way to get around the power requirements for an efficient bandmill you will need in the neighborhood of 20 HP minimum, and more to drive the pump would be better. It will take serious oil volume to drive the bandwheels with the speed and power needed, not to mention keeping it cool. Belts are a much more efficient way to transfer power, and hydraulics for feed and functions. Frank C.

I was anticipating around a 25-30HP engine to power the hydraulic power pack figured that should give me close to 20HP but the torque is much higher than say gas unit and the head doesn't have to weigh as much. The power packs come up for sale used around here somewhat often, not sure I'll go this route but it was an idea, I think it would be simpler to build with hydraulic but sourcing the parts would be easier without.

Magicman · July 07, 2014, 01:25:54 PM

Hello cib, and Welcome to the Forestry Forum. 8)

cib · July 07, 2014, 02:18:12 PM

Quote from: Magicman on July 07, 2014, 01:25:54 PM
Hello cib, and Welcome to the Forestry Forum. 8)

Thanks. I've read the forums off and on for a couple of years. I live in NW Indiana right now but my family has a farm in central/south Georgia. The wife and I are moving back in a year or two. I visit fairly often and build things around the farm and try to help the family out. One of the things is we've got a lot of things to fix up and need a lot of wood to do it.

Magicman · July 07, 2014, 03:18:48 PM

There are several FF members in Ga, so you have plenty of company. We just attended a "Sawing, Eating, & Visiting" in May: LINK

jbpaxton · July 07, 2014, 05:52:29 PM

A variable displacement pump w/closed center valves (hydraulic system) is much more efficient than a open center fixed displacement pump system, especially if you are running more than one operation off of the same pump. It will cost more to set up but will save in the long run. A good vari-displacement piston pump will run a 2500 to 3000 psi system, which transmits the same HP @ about 1/2 the flow of gear pump system, less friction line lost-less heat, smaller cylinders, and smaller displacement motor, smaller cooler for the same HP. If you would like some help on
the hydraulic questions on this PM me.
Jim

dun that · July 08, 2014, 10:49:09 AM

What exactly would it take to be able to run a saw on hydraulics with 19" wheels, i think 20 hp would be enough on the band, so how big of a pump, and how big of a hydraulic motor would it take. i know heat is a big factor, while it will take a bunch of hp, arent a lot of sawmills running 24 hp or more? i was thinking you would still want to use a belt drive the wheels from a hydraulic motor. I can buy a 60 hp motor or bigger 1/3 the price as to buy a b&s 24 hp or bigger brand new.you could sure do a lot with 60 hp. I know logmaster built a hydraulic driven mill, does anyone on here have one? I would like to see the specs on one that was manufactured. Its was put out there i would just like to know what it would take.

cib · July 08, 2014, 10:37:18 PM

Quote from: dun that on July 08, 2014, 10:49:09 AM
What exactly would it take to be able to run a saw on hydraulics with 19" wheels, i think 20 hp would be enough on the band, so how big of a pump, and how big of a hydraulic motor would it take. i know heat is a big factor, while it will take a bunch of hp, arent a lot of sawmills running 24 hp or more? i was thinking you would still want to use a belt drive the wheels from a hydraulic motor. I can buy a 60 hp motor or bigger 1/3 the price as to buy a b&s 24 hp or bigger brand new.you could sure do a lot with 60 hp. I know logmaster built a hydraulic driven mill, does anyone on here have one? I would like to see the specs on one that was manufactured. Its was put out there i would just like to know what it would take.

Most pumps are 85% efficient so if the engine is only 20 HP then you lose 15% right off the bat you only have 17 HP that is coming out of the pump then friction losses in the line and friction loss of the motor driving the band you're likely looking at 15 HP at the band wheel. The good thing is that with a direct drive 900 RPM would get you 4,200 SFPM roughly so you'd have decent speed.

The size pump depends on the type of motor, I'm working those details out right now but the motor would need roughly 2500 PSI at 14 GPM flow to hit just over 20 HP. Hydraulic HP is calculated based upon pressure and gallons per minute.

There are guys on here that know a lot more about me about hydraulics, I'm just an ole farm boy. I'll post up a bit more tomorrow when I've had time to wokr out the details more.

The reason you state is the reason I wanted to go hydraulic, I could get a bigger engine for far cheaper than a small diesel or briggs.

I can get a 30-50hp engine for very cheap and set up my own power pack to run the entire mill. The pump is a deciding factor for me. Once I figure it's cost I can compare the 20-25 hp small engines vs a larger cheaper engine with hydraulics.