PTO powered bandmill

[tuolumne]

I have posted a similar thead in a DIY bandmill forum, but TBN sees way more traffic and I have always valued the input from here very much.

I am looking to build a sawmill to turn my pasture/field clearing project into saleable (and usable for me) product to help support our homesteading efforts. I do not intend to have this be a portable sawmill at this point. I am looking to build something that looks like a Linn Lumber cutter head as on many home-built mills, but fixed rather than moving. Help me explore why are others not using this power option on small mills. This will be a horizontal bandsaw mill, not a circular saw.

For me, it seems simplest to power a stationary cutter head from my tractor PTO and thereby avoid another engine to maintain. Also, I have 37 HP available and I think I could maintain acceptable torque at lower RPMs to save on fuel and noise. Tractor hydraulics would also then be availabe for future carriage drive motor, hydraulic turner/clamping system etc. I could have a gearbox in the carriage that moves up and down within normal limits of 3PH movement for the drive shaft. Why haven't I seen others doing this? Please add to my pros and cons (or refute them!) I will edit this post to keep all pros and cons current at the top of the page. You'll notice that most of my cons have an argument noted afterward, so you can see that I am personally biased.

Pro:
-Already have an engine with lots of HP and hydraulic function.
-Stationary cutter=stationary sawyer.
-Log weight on moving carriage is enough to preven vibrations/fixed cutter head wold be more stable. Likewise, band carriage is fixed to rails.
-Log load and board stacking on same side of machine
-Variable band speed using engine rpm depending on log, moisture etc.
-Saw under shed with engine outside for fumes
-Sawdust all in one pile

Con:
-Longer rail bed to accomodate moving carriage for logs (more steel): seems simple enought to build, It would need to be about 22' long for a 9' carriage to handle 13' logs with a bit of cantilever and works in CAD so far
-Sawdust will be headed toward tractor with drive wheel on that side; it could be directed a bit I imagine; better than scattered along the whole rail on the operator side like most portable mills.
-Band always running? I could rig a switch to the operator area from the tractors' "operator presence" to kill the PTO in an emergency.
-Tractor must be disconnected to load logs; perhaps 8 at a time on a loading rail. I need a break from sawing anyway.

Thanks!

 

[irvingj]

Wow- sounds very ambitious! Don't know anything about mills, but I'll be watching this post (I have a lot of trees I'd like gone on my land...). Thanks in advance for future updates. WBB in NH

 

[Rod in Forfar]

I buy quite a bit of lumber from a local farmer who has a circular saw mill which he runs off a 60 hp Ford tractor. Even it doesn't seem to have any too much power, as I noticed the rev's dropping while he cut 12" boards off a pine log the other day.

The pros:

A pto-driven circular saw mill is fast and seems to run for quite a long time without significant maintenance.

Fuel cost per hour to run the mill is significant, but for low-value logs it's a cheaper way to turn them into lumber than the labour-intensive band mill.

The cons:

It takes up a lot of space and equipment. Two tractors are needed at a minimum, one to run the pto and another to handle the logs. Both are over 60 hp, but this is a farming operation where there's no shortage of power equipment.

This mill isn't very accurate. The precision control of board thickness is a major plus for a band mill.


A fixed-location band mill would require much less power than a circular-saw unit.

Another local mill has a home-made resawing unit set up much as you describe, driven by a 40(?) hp Massey-Ferguson. The pto shaft gets in the way and is a safety factor, in my opinion, though the narrow kerf saw has been a profit generator for many years for Ralph Oosting of Smiths Falls, Ontario.

The other mill where I take my black walnut is an early Wood Miser gas-powered band mill set up inside a shed. Its owner does an excellent job of sawing, though production is slow and thus it's quite pricey for low-value stuff like basswood.

If I wanted a personal mill and had access only to one tractor, I'd look until I found a Wood Miser owner ready to retire and buy the thing. It's safe and precise, if not overly productive. "Two outa three ain't bad."

 

[tuolumne]

...The pto shaft gets in the way and is a safety factor, in my opinion...."

Said to a fellow who got tangled up in a PTO shaft once! All activities will take place on the opposite side of the mill from the tractor.

Also, as I clarified in the original post, this is to be a horizontal bandsaw mill. Most portable versions run something from a 10-30 HP dedicated engine on the size mill that I am considering.

 

[BHD]

Lindsay's Technical Books at one time they had a book on the old type of saw mill

but if your going to try that I think I would consider building a normal type of band saw mill, and then just use Hydraulics to power it, yes a few hoses would be needed, but it would save a hole lot of problems in redesigning the unit and you remove the hazard of the PTO shaft, if your tractor does not have enough Hydraulics to operate it then consider a PTO powered pump, but then you can make a entire Hydraulic operated unit,

one of the considerations I had when I built mine was how heavy a log is and I built mine on the ground, (it sets flat on the ground) so logs do not need to be lifted, just rolled, on to the bed,

with Hydraulics you have a valve, and no need of a clutch, of any type, and there are a lot of plans out there, little to engineer, or redesign.

below is what I built nearly 20 years ago, no it is not hydraulic powered, but would be simple to power it with a hydraulic motor of the proper type and RPM.

put up a line with a few rings on it so the hose does not get tangled,

you can see how the bed is on the ground,

 

[tuolumne]

I have looked at the hydraulic option a good bit. This would involve a number of extract components that would raise the price over the PTO option.

Now that I think about it, the PTO switch on my JD3520 is electronic. It seems feasible that this could be switched from the sawmill operator station and have a pigtail to plug into the tractor.

 

[kennyd]

Now that I think about it, the PTO switch on my JD3520 is electronic. It seems feasible that this could be switched from the sawmill operator station and have a pigtail to plug into the tractor.

Except that the RPM of the tractor will have to be reduced before you engage it, and brought back up after it's running. It would however work as a good emergancy kill switch.

 

[tuolumne]

Except that the RPM of the tractor will have to be reduced before you engage it, and brought back up after it's running. It would however work as a good emergancy kill switch.

This has always been my practice with the wood chipper. With my rototiller, I have turned the PTO on and off while at full RPM. Is this a problem? The rototiller seems to have almost no startup load when it is out of the ground. Like the rototiller, a bandsaw would have a very small startup load compared to a wood chipper. What is the reason behind this practice?

 

[kennyd]

This has always been my practice with the wood chipper. With my rototiller, I have turned the PTO on and off while at full RPM. Is this a problem? The rototiller seems to have almost no startup load when it is out of the ground. Like the rototiller, a bandsaw would have a very small startup load compared to a wood chipper. What is the reason behind this practice?

That is NOT good for the PTO clutch!

From the manual:

Engaging Rear PTO Only

1. Sit on operator痴 seat.
2. Stop machine motion and push all PTO engagement knobs to the disengaged/off position.
NOTE: The starter will not crank if the rear/mid PTO knob is pulled to the engaged/on position. If the operator leaves the seat with the engine running and the rear/mid PTO engaged, the safety interlock system will stop the engine and all implements.
3. Reduce throttle setting to 1500 rpm.
4. Move the PTO selector lever to top/rearward position for rear PTO only.
5. Pull the rear PTO engagement knob to the engaged/on position to engage the rear PTO.
The instrument panel PTO engaged light will illuminate when the rear PTO is engaged.
6. Adjust the hand throttle lever forward to the desired speed for implement used.
NOTE: The PTO marker on the tachometer indicates engine speed for a standard 540 PTO.
Disengaging Rear PTO

1. Adjust engine rpm to low idle.
2. Push all PTO engagement knobs to the disengaged/off position to disengage the rear PTO.
The instrument panel PTO engaged light will go out when the rear PTO is disengaged.

 

[tuolumne]

Thanks for the warning; I'll be more careful.