building a bandsaw mill

[muddstopper]

I have been thinking about building a band mill for a few years now, and it most likely wont get build this year either. I have way to many things going on right now to start another project. I do have a few questions I want to ask so I know what to keep a look out for as I am running up and down the highway trying to make a living.

First off, I want a mill large enough to saw out a table top so I am thinking about making a mill capable of handling a 4ft dia log. I know, I probably wont see many trees that size, so what are the drawbacks of having a mill capable of sawing 4ft when most logs would probably be 2ft or less. I am thinking a 24ft bed for 20ft long logs with plans for extensions if I find the need.

Second. How wide/thick of a blade should i be thinking about using, and what dia wheels for the blade to ride on.

Third, what kind of HP should I be looking for. I have a 50hp iszusu diesel not doing nothing I was thinking about using. It being water cooled I might try to find something else to use. Just need an ideal of what size I should be looking for.

I figure on running the saw off the diesel engine, but use hydraulics to pull the saw thru the timber. Probably build a log lifter and clamp system using the hydraulics as well.

I can use all the ideals I can get, so lets hear what you have to say.

 

[muddstopper]

Nobodyhere run bandmills?

 

[BobL]

Lots of people here running band mills nut not so many building them.
I suggest you look a commercial saws and see what their specs are.

One thing I can comment on is using hydraulics to move the mill/log etc.
My understanding is that most people underestimate the power needed for hydraulic operations and that you need to double the engine power required to cut the log to move the mill/logs etc.
I think the Cooksaw with the 36" cut and full hydraulics uses a 67HP motor so 50HP to cut/move 48" logs is not going to be enough.

 

[muddstopper]

Looked up the Cooks 36"cut mill. It is fully hydraulic and comes with several engine choices from 37hp gas to 62hp perkins diesel. I dont believe the big hp is needed for the hydraulic system, most likely it is needed for the large dia wood. At over $25 grand, I wont be buying one of their mills and feel I need something a lot simpler. I dont have any plans of going into full time lumber milling.

My reasoning for even wanting a band mill is to build my retirement home. Probably build a few out buildings and such, and then just sell the mill. I have the timber needed so rather than buy lumber, I want to just mill my own.

My reasoning for wanting to go hydraulics is simply because i am getting to old to push a mill thru logs by hand. Torn rotator cuffs, and the brothers, Arthur and Rummy, always picking on me, limits the physical amount of work I can do. I maight just look for a used band mill and adapt hydraulics to it. It doesnt have to be super fast, just super consistant.

 

[mesupra]

I have a Hudson Farm boss 36 with a 23 hp Briggs, it does not run any hydros, just the band. I absolutely love the motor, very smooth running, easy starting. In pine it does just fine with a decent band. I can see how more bower would be nice in hardwoods. I can't imagine 50hp not being enough.

 

[kimosawboy]

In one paragraph you want 48" and in the other you state you just want to ''build a few out buildings and such'', the two area at far opposites of the spectrum.
Have you given any thought to gas/diesel vs. electric, you really cannot decide on an engine until you have a few basics ..size of mill/stationary/add ons/$$$.
I can understand the wanting of hydraulics but again do you have the $$ or the experience to work with them??
Usually I don't mean to intentionally rain on someones parade, but I really hope that you know what your are getting into...a little bandmill is one thing but a mill that you want is at the other end of the spectrum.

G Vavra

 

[muddstopper]

As for experience, I have been working in timber for over 50 years. Circle saw milled with my Grandfather. Just never have fooled with a bandsaw mill. My experience working with hydraulic systems is almost 40 years. I think I can design a simple system to run a bandsaw carrage. I dont intend to run the band off hydraulics, just the feed, clamping and log lift. Probably mount a DRO to set blade height and keep it simple using lead screws and a hand crank.

Now I know I wont be sawing many 4 ft dia logs, but my screwed way of thinking is if I am going to build a mill, I can build a big one for about the same money as building a small one. Buying everything new, maybe not, but the hoarder in me will pick up every piece of scrap material that I think might be useful. I am not beyond spending the day in the scrap yard removing parts off of old scraped equipment. Which is the reason I started this thread, just to get ideals of what materials and kind of parts I will need. I dont intend to start this build today and figure I have enough time to source most of the materials needed.

 

[olyman]

their is a guy down south somewhere,,that built a mill that big..used a international bus frame for the carriage....you got your length,,and strength...and binder bus frames,,are straight from end to end. at least the older ones are.....may need to grind rivets,,and weld instead, but so what??? premade carriage!!!!!!!!!

 

[muddstopper]

The bus frame is a good ideal and worth considering, or at least looking into. Welding might be easy, but forget trying to drill a hole.

 

[BobL]

Looked up the Cooks 36"cut mill. It is fully hydraulic and comes with several engine choices from 37hp gas to 62hp perkins diesel. I dont believe the big hp is needed for the hydraulic system, most likely it is needed for the large dia wood. At over $25 grand, I wont be buying one of their mills and feel I need something a lot simpler. I dont have any plans of going into full time lumber milling..

Yes of course I was referring to large diameter wood - you did after all mention a 48" cut.
The Big Cooksaw is indeed fully hydraulic but not the cutting - this is still done by the motor.
It all depends how quickly you want to be able to do things.
The miller I know with the 62HP Cooksaw reckons this is still not enough power or the hydraulics in a 36" cut and is looking at upgrading or a 70+HP motor.
AS you know with hydraulics you can use a small pump/motor to move things slowly or bigger pump/motor to do things quicker.
After a about five minutes use, slow hydraulics is just a major PITA.

 

[muddstopper]

Adding a 72 hp motor to your friends band mill isnt going to help the hydraulic as far as speed or power. He can put a jet engine on it and unless he starts changing out pumps, valves and hydraulic motors, the hydraulic system will still be the same as it is with the smaller engine. I dont know the spec's of the Cooks hydraulic system. If the hydraulics are bogging because of a lack of engine hp, then yes a bigger engine will improve things, but I suspect thats not the case. In the event that his hydraulic motor for his feed uses 10gpm oil @3000psi, then he would need close to 20hp just to move the carriage. Most likely that is not the case, I would expect much lower PSI and probably a much lower flow rate, 3-6gpm at 1500psi would probably be more with what the system is designed for and that would only require around 3hp, 6gpm would take 6hp. I suspect your friends speed concerns are with the actual sawing of the lumber which is where the larger hp will make a difference.

Just looked it up and cooks hydraulic motors are 2.2cuin at 12gpm and max 1800psi, so about 14hp to run 959 rpms. If the motor is actually using that much oil@max pressure and turning that many rpms, I think it would be pretty darn hard to keep up with. Assuming a 60pitch drive chain, the smallest sprocket for a 1 in shaft is a 10tooth and at 2 3/4 dia the carriage would be traveling at 8000+ IPM. Thats a 689ft long log in about a minute. My money is on lower oil flow and pressure rates to reduce speed. Cooks also uses two different size pumps, a 9gpm and a 14gpm, both rated at 4000rpms, both standard gear pumps. I also doubt that any of cooks engines are turning that kind of rpms so I think its also a safe bet that their hydraulic pumps or motors arent running at rated capacity. I would venture to say, and its just a guess, that the 9gpm pumps are used on gas engines running 3200rpms and the 14gpm pumps on the diesel engines turning around 2000rpms. Those rpms would put either pump flowing around 7gpm, which is close to my original first thoughts on the subject. If your friend wants to increase his hydraulic speed, just tell him to rev up the engine.

There are more than a few things I dont know about the cooks mill, or any other band mill for that matter. I am just now starting to research them so I might not understand just how much of the engine hp is dedicated to the Hydraulic system, but if the same mill will run with a smaller engine and without any changes to the hydraulic system actual flows and pressures, I would think that hp upgrades are more for the benefit of the saw blade than they are for the hydraulic power.

 

[olyman]

The bus frame is a good ideal and worth considering, or at least looking into. Welding might be easy, but forget trying to drill a hole.

carbide bit.....

 

[muddstopper]

carbide bit.....

M42 colbalt for the really hard stuff

 

[olyman]

M42 colbalt for the really hard stuff

me thinks, frame rivets aren't REAL hard.. a normal high speed bit,, turning slow, may countersink the hole,, for welding shut...

 

[Franny K]

To do the four feet you want you will need I suspect a two inch blade or something even larger that real commercial mills use. I use 1 1/4 blades. What is going to happen is you get band wheels for the larger blade and running the smaller one will perhaps take changing out the wheels. I am told I can run 1 1/2 blades but have to re adjust, not really sure how far 2 inches is good for I think woodmizer has a semi commercial I would call it mill good for 4 feet. The bigger the blade the more tension and then the more rubust the machine must be. It sure will make the bands longer and more expensive. Did you forget about turning the log hydraulically or have a machine or winch in mind for that. Hydraulic stuff is expensive at the retail level the manufacturers can't be paying the kind of prices I have to for hoses and valves and fittings and the like for my heavy (ish) equipment.

 

[BobL]

Adding a 72 hp motor to your friends band mill isnt going to help the hydraulic as far as speed or power. He can put a jet engine on it and unless he starts changing out pumps, valves and hydraulic motors, the hydraulic system will still be the same as it is with the smaller engine.

Yep he plans to do that as well - he's also tossing up whether it's worth doing that or build a completely new mill.

 

[muddstopper]

To do the four feet you want you will need I suspect a two inch blade or something even larger that real commercial mills use. I use 1 1/4 blades. What is going to happen is you get band wheels for the larger blade and running the smaller one will perhaps take changing out the wheels. I am told I can run 1 1/2 blades but have to re adjust, not really sure how far 2 inches is good for I think woodmizer has a semi commercial I would call it mill good for 4 feet. The bigger the blade the more tension and then the more rubust the machine must be. It sure will make the bands longer and more expensive. Did you forget about turning the log hydraulically or have a machine or winch in mind for that. Hydraulic stuff is expensive at the retail level the manufacturers can't be paying the kind of prices I have to for hoses and valves and fittings and the like for my heavy (ish) equipment.

I am thinking 2in blades running on trailer tires/wheels instead of forking out the cash for large bandsaw wheels. I do plan on a hydraulic log turner. Heres the thing, if you are turning the log, lifting the log running the carriage up and down, or sawing wood, your still only using one hydraulic function at a time. Adding other functions doesnt increase the size of the overall hydraulic system, unless you are trying to do multiple functions at the same time. Engine hp requirements vary according to flow and load. If your pump is capable of pumping xgpm at xpsi, but the functions doesnt require but half that, then engine hp required will be reduced. Where lifting the log from the ground might take 5gpm@3000psi, the log turner might just need the same 5gpm at only 1000psi. The pump wont make the extra 2000psi pressure unless the load requires it. Size the pump and engine requirements to the largest load and the lighter loads will take care of themselfs.

 

[Franny K]

I do plan on a hydraulic log turner. Here is the thing, if you are turning the log, lifting the log running the carriage up and down, or sawing wood, your still only using one hydraulic function at a time. Adding other functions doesnt increase the size of the overall hydraulic system, unless you are trying to do multiple functions at the same time. ...... Size the pump and engine requirements to the largest load and the lighter loads will take care of themselves.

That isn't exactly the way it seems to me. Mine some functions can be done at the same time and some seem to have priority. The log loader which I think you don't want is slow and really needs run at high engine speed, I don't think other things work at the same time, one might want to move the stops, clamp, blade motor assembly or turner at that time, especially on the way down. If you make a lot of flow most likely the things that work on small cylinders or motors will go fast at blade speed motor operation. I have the chain type turner and definitely use the raise and lower the implement and rotate the chain function at the same time. The running the carriage up and down is touchy at high rpm and the loader is the only thing really slow at least on what I have.
Guys on internet forums say run another function at the same time as the up/down but that makes no difference on my set up. It is kind of strange how some things take precedence over others, kind of like an ag tractor either the remotes or the three point hitch take precedence.

 

[muddstopper]

Franny, what you are describing is exactly what happens with open center hydraulics. All the flow and pressure is going thru one valve bank and depending on which valve you are using at the time, it can and will take precedence over other operations. Using more than one function at a time, power is robbed from each function making both functions slower. Stop using one function while still operating the other function will cause erratic operation such as things speeding up unexpectantly. Some things can be done to limit the erratic behavor. The use of flow control and pressure reducing valves are a couple. I dont know anything about how manufacturers plan their hydraulics. I havent even looked at any. I do know that adding flow controls and pressure reduceing valves will add cost to any piece of equipment and complicate the plumbing. When it comes to ag tractors, a lot of manufactuers have gone to close center hydraulics and axil piston pumps. Where as if pump senses the load and then supplies flows and pressure to cover the need.

Your comments sort of confirmed what I had already suspected and my comments about sizing for the bigger loads and letting the smaller loads take care of themself, is still true, you just also have to plan for the extra plumbing to keep things working consistantly as they should. And example of what I am talking about, Lets say your log lift is the biggest load on your hydraulic system and it takes 5gpm at 2500psi to operate the way its supposed to. Then you also might want to run your carrage back and forth at the same time and it also takes 5 gpm@2500psi. You would size you pumps and engine hp to run 10gpm at 2500psi. Now if you plumb the 10gpm thru one multispool valve you would have 5gpm available to run both operations at the same time, but if you only ran one function , it would get the full 10gpm, making it twice as fast as you want it to be. Now add a divider valve that splits the 10gpm into two seperate 5gpm flows and use two seperate control valves instead of a multi spool control valve. You would have 10gpm of oil available and only 5gpm equally divided to each function. This would stop the speeding up and slowing down of either function in the situation where you only want to run one function at a time. in this example you have the amount of oil flow you need to run everything at one time, without the erratic behavor of only runningone function at a time or running one function and then midway using the other function at the same time. This example was using a dividied flow at equal pressure. Lets say you only need 1500psi to run the carriage, but 2500psi to run the log lift. This is where you could use either a pressure reduceing valve to lower pressure for the saw circuit, or you could add a relief. Pressure reduceing valves and reliefs work similar in function in that both limit the available amount of pressure downstream. Hard to describe, but a relief works by letting the pump build full pressure and then dumping the excess over setting back to tank. A Pressure reducing valve dumps all oil back to tank and is adjustable to only allow the needed pressure to go toward the operation. In other words, a relief redirects pressure from the operation and a reducing valve redirects pressure for return. Because of this, reduceing valve dont create the same heat that a relief valve does. Not to confuse a pressure reducing valve with a flow control. Flow control choose which direction flow goes, either to function or to tank. A reducing valve controls pressure either to function or to tank. All of this takes extra plumbing and form what you are describing with your mill, I suspect isnt being used.

 

[muddstopper]

I understand what you are saying. Let me first say, I havent even looked at a hydraulic mill, so I dont know anything about how they plumb their hydraulic systems. I do know what you are describing is typical of a open center hydraulic system using multispool control valves. I still stand by my statement of sizing the pumps and hp to match maximum requirements. The part of letting the smaller function take care of themself probably needs some clarifying. If you need 5gpm at 2500psi to run your log lift and another 5gpm @2500 to run everything else, you would size your pump and hp requirements to provide 10gpm@2500psi. Now if you plumb this flow to a multispool control valve, you have the 10gpm you need to run everything at the same time, but if you only need to run one function, it would get the full 10gpm@2500psi making the operation twice as fast as you intended for it to be. Kind of the problem you are describing with your mill. Running everything at the same time might help, but if lets say your log lift had a little log and didnt need the full 2500psi to load the log on the deck, well flow will take path of least resistance and the log lift could just sling up and throw the log over the deck. To get around this problem cost money. If instead of multispool control valve, you used 2 seperate control valves and a flow divider valve to split your 10gpm flow into two seperate flows. Now your log lift would always have the 5gpm oil flow and 2500psi available and wouldnt be subjected to the flow requirements of other functions. Now suppose your other functions only needed 1500psi to do what they do, well, your pump is putting out 2500psi so somehow it has to be lowered. This can be done in two ways. Common method is adding a adjustable relief valve and the other is using a pressure reducing valve. ( I bet your mill already has some sort of relief valve somewhere in the system). Both type valves regulate pressure, they just do it in different ways. A Relief valve allows the pump to build full pressure and dumps the un-needed pressure back to tank, building heat in the process. A pressure reducing valve restricts flow to tank and only lets the pump build the amount needed. Reducing valves dont create the heat a relief valve does. End result is the same, just less heat.

I can understand why a manufacturer might not want to incorporate some of the things I mentioned. They cost money, require more plumbing and hydraulic hoses and make price point for their equipment much higher. A multispool control valve running everything is a lot simpler and cheaper, but that doesnt mean you cant change or add additional valving to your personal equipment.