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Seeking source for education in "sound" bandsaw mill design and construction.

Started by MikeySP, October 02, 2018, 05:56:56 PM

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Ianab

Quote from: JB Griffin on November 03, 2018, 09:26:44 PMIt don't take much power to turn wheels. What takes torque is keepin em going. Bigger wheel (read heavy) act and work like flywheels storing energy. 


Also, a larger wheel (but the same band speed) means you can gear down the drive pulleys more, and that increases the torque, to make up for the larger wheel dia. So actual power requirements should be similar. 

The larger wheels should help band life as it reduces the flexing on the band each time it goes around one, and there is the flywheel effect too.

Commercial mills are always a trade-off between cost and capacity, and then you add in the portability thing as well. I'm not sure what size wheels a WM1000 has, but I know it's neither cheap nor very portable. ;) 
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Den-Den

Longer blades cost more, they also last longer which cancels out the extra cost UNLESS you hit metal.
You may think that you can or may think you can't; either way, you are right.

JB Griffin

2000 LT40hyd remote 33hp Kubota with 6gpm hyd unit, 150 Prentice, WM bms250, Suffolk dual tooth setter

Over 3.5million bdft sawn with a Baker Dominator.

mike_belben

I dont mean to pick on ya but i dont think thats entirely correct on the bandwheels diameter influence on torque.  The bigger diameter will cause higher surface feet per minute band speed but due to the longer radius that the big wheel is applying force to the band, torque into the band is reduced. (Well, load to the engine is increased by working through a longer lever of disadvantage. Whether torque output from the engine increases or not depends on whether the engine had more to offer or not.  You cannot create power without a load to dissipate the power into.)

regearing to correct band speed upon a wheel diameter increase will then increase torque into the band wheel's shaft but im not sure on the tire surface.  i believe the two cancel each other out.  If you go up 20% on size youll put 20% more load into the shaft and need a 20% regear to go back to prior condition.

If you put taller tires on a truck you go faster at the same engine RPM and have less pulling capacity.  You regear to correct the tire change and your MPH/RPM relationship is restored but no extra torque is created by this [if we are talking about a 1:1 drive ratio]

Where gearing gives you more torque to apply to the load is when you down shift a gear while running the same tire size.    More cycles per minute carry the load.  Basically each piston is biting off a smaller bite when it spins faster.  

Im still unsure actually.. Starting to waffle on it myself.  And it really doesnt matter much, i just like the physics discussion of it. Keeps my brain occupied.

'Big band wheels are gonna need a big motor' is an oversimplification that should hold fairly true. 
Praise The Lord

Hilltop366

If the band speed stays the same (feet per min) a larger band wheel will weigh a bit more and will require a bit more power to spin but I'm thinking the effect will be minimal when you take into account the rest of the spinning mass in the hole system (engine, pulleys, shafts) perhaps there will be some fly wheel effect if the wheel was a lot heavier and larger, that would be ok if the cut is only a few seconds but with a longer cut ripping logs I'm thinking a lot of flywheel effect would be your enemy by working against you after the first few inches of cut.

The trick is finding the happy medium for your intended use which I think would be to start with the log and work your way from there, will keeping your budget in mind.

Log size and species = band size and type?

Band size ? = band wheel size and band speed?

Log size and band size and type and band speed = power requirement ?

Band wheel size ?  and band size ? = shaft and bearing size ? 

And on and on.....

It keeps going until the mill is sitting on the ground.

A person could start somewhere else in the equation and build around a different limiting factor for a component you already have like band wheels or engine and see if the end product would fulfill your needs.

IMHO








charles mann

Quote from: MikeySP on October 27, 2018, 11:34:09 AMCurious as I am not married to any design yet aside from hydraulics, band sawmill, and 44HP diesel as I have these already. I say this because 36" wheels would create a problem an oversize load or very small log diameter limit in a mobile mill.
I will be running into this issue. Nearly 11' wide for the saw head beam, im having to design a way to turn the entire carriage 90 degrees to transport it, then put it back into saw position once its moved. 
Iv got a few "designs" but not sure if any will work without potentially causing damage to the carriage assy. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Wintergreen Mountain

 Charles;
  Check out   canadianwoodworkers  posts. He modified his single post Wood-Mizer so the head telescoped, from the original throat, to about 20 or so inches wider throat. Might give you some thoughts.
  LEON
1920 Ford 4x4 tractor, forks & bucket. 2010 36" Turner Mills band mill. Cat-Claw blade sharpener. Cat-Claw Dual Tooth Setter. Cat D3 crawler dozer. Cat 215c excavator, Ford L9000 dump truck. Gardner Denver 190 portable air compressor. KatoLight 40Kw trailer mounted gen set. Baker M412 4-head planer.

charles mann

Quote from: Wintergreen Mountain on November 04, 2018, 06:15:24 PM
Charles;
 Check out   canadianwoodworkers  posts. He modified his single post Wood-Mizer so the head telescoped, from the original throat, to about 20 or so inches wider throat. Might give you some thoughts.
 LEON
I did check it out, and it would work, except the saw beam itself, even if i took the drive wheel off, just the sq tubing is just under 11'. 
Now, i could cut the sq tubing in half, weld up a slide box out of 1/2" plate and plug weld some more 1/2" inside the sq tubing, where i could bolt the slide box to the 2 halves of the beam. Not sure, probably 95+% chance, it would hold up, and i might go buy another stick of 5"x5" sq tubing and give it a try. I mean heck, if it doesnt work, im only around $400. I spit more than that every year in copenhagen, which is a constant outgo, as where the mill has a chance of being ingo. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Crusarius

make a cantilever style head and put a rotating bearing on it to rotate the entire saw portion.

charles mann

Quote from: Crusarius on November 05, 2018, 07:22:03 AM
make a cantilever style head and put a rotating bearing on it to rotate the entire saw portion.
Cantilever 1400 pounds? That'll be a heck of a design feat. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Crusarius

your mill needs a diet :) 

it can be done. just need to look at counterweights and proper geometry.

mike_belben

Use a HD truck axle spindle and hub from scrap yard.  And have support post to lock it into for the travel position.  Keep the brake caliper for controlling the swing speed, you can engage the pads with a simple hand cam.  

Or buy a dead bucket truck manlift crane and repurpose the base.  Theyll have a brass worm gear hydraulic rotatry base similar to a mini ex sort of and easily handle the weight. A large machine shop rotary table could also.  Those are worm gear too. You can adjust the tolerance by gib screws on those usually. But a truck axle is surely cheapest for most of us.

Look at building cranes.. Single upright, 300ft long jib spar, big counterweight off the back.  Been in business for a few hundred years now, must work half decent.  Your engine is the counterweight.  Because fuel tank levels vary i would locate that near the pivot to reduce its influence on lumber finish.  If it has to be at one end or the other, oppose its weight with a sliding weight on the other side.  Like an old doctor scale.  Tank gets filled, slide the weight the other way. 
Praise The Lord

Hilltop366

I was thinking a bottle jack in the centre under the saw but once the saw carriage is off the ground things could get tippy.

So next thought is a turn table, have a section of track (double frame) that turns on a centre pivot and has guide bearings under that ride on a circular rim to keep it stable. The track would be cut on a angle so it returns to the same position and can't go past the normal running position.

charles mann

Quote from: Crusarius on November 05, 2018, 09:28:26 AM
your mill needs a diet :)

it can be done. just need to look at counterweights and proper geometry.
Then it wouldnt cut the width im building for. Now, i could go to an electric motor and loose 400-500 lbs, or go to a small gas engine and loose bout the same wt. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

charles mann

Quote from: Hilltop366 on November 05, 2018, 11:33:31 AM
I was thinking a bottle jack in the centre under the saw but once the saw carriage is off the ground things could get tippy.

So next thought is a turn table, have a section of track (double frame) that turns on a centre pivot and has guide bearings under that ride on a circular rim to keep it stable. The track would be cut on a angle so it returns to the same position and can't go past the normal running position.
Turn table is my thought process too, and have thought about the the spindle and brake system from a semi truck. 
Just lifting the carriage is where it gets sketchy. But if using a turn table, 2 hydraulic cylinders on a porta power pump, attached to the table, then to the beam would provide a bit more stability than a single. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Hilltop366

At 1400 lbs I figure it could be turned by hand fairly easily when you think of how much a person can push with something like a pallet jack on a hard smooth surface. 

Add a place to put a pole or a peavy on the side and you have just increased your leverage and reduced your effort considerably.

MikeySP

Thanks for all the comments!! We picked up the bandsaw. A Peerless 3000-MS with 30" wheels. This thing is enormous. Anyways, the wheels are 30" and ride on 1-1/2" axles. Much to cannibalize off of it for the build. QuestionWS\: How do I estimate if it is beefy enough for my purposes? Is it trial and error? I ask, because I got it for a song and could sell the thing at a descent profit and pick up a set of "proper" wheels. I like the idea of using these wheels as it has many mechanisms I can utilize such as tilting wheel adjustment for toe-in/out, Tensioner, Bearings, axles, Engine slide tensioner, etc..

What say ye Gents?



 

 

 

 

 

charles mann

how wide of a band will the wheels accept? if you c\are cutting fairly wide, your band needs to be wide too. since I'm going nearly 6' wide, many, including the blade sales rep with WM and Cooks said no less than 1.5" inches, so i went with 2" for everything, allowing me to drop down to a 1.5" at a later date once resourcing 60"+ trees is limited or non longer worth the effort to gather.
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

charles mann

Quote from: mike_belben on November 05, 2018, 10:13:22 AM
Look at building cranes.. Single upright, 300ft long jib spar, big counterweight off the back.  Been in business for a few hundred years now, must work half decent.  Your engine is the counterweight.  Because fuel tank levels vary i would locate that near the pivot to reduce its influence on lumber finish.  If it has to be at one end or the other, oppose its weight with a sliding weight on the other side.  Like an old doctor scale.  Tank gets filled, slide the weight the other way.
I figure if a cantilever design is to be used, it'll be on vs 2.5 and will be able to mock up something. i figure putting the fuel cell at bed rail or below will drastically minimize or fully negate the need for a counter weight as fuel is burned. it will be below the cg point and an electric lift pump could be used to push fuel to the injector pump. 
im not sure if i can explain my method of building the guide rails for the mill to travel horizontally. but here goes. buy some thick tubing, say, 2.5" in diameter with a 1/2" wall thickness and basically copy the WM design. use 4' of 3" sq tubing and some 1/4" UHMW to glide down the 2x6 bed beam. i figure if i can make the engine hang off far enough, but yet still keep enough downward pressure on the guide rails, it will also put enough side loading pressure on the     sq tubing and uhmw, causing it stay "true". that is until the plastic wears down enough, that I have to replace the plastic. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Southside

Quote from: charles mann on November 05, 2018, 09:39:08 PMi figure putting the fuel cell at bed rail


Are you going to cat track your fuel line from the tank to the engine?  Definitely would want a skid plate around the tank as a lot of debris falls and or can gather under the mill, nubs and limbs not cut flush along with butt swell and sweep will protrude down below the rails, not to mention transport hazards of stumps, sticks, and other log trash.  
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

charles mann

Quote from: Southside logger on November 05, 2018, 10:26:30 PM
Quote from: charles mann on November 05, 2018, 09:39:08 PMi figure putting the fuel cell at bed rail


Are you going to cat track your fuel line from the tank to the engine?  


Naw, set the cell in a mounted frame that is bolted to the lower carriage rail with a qd fitting for fuel out and return line. a 5 gal tank won't weigh much, and it would be riding on the outside of the bed beam. look at it as riding to the outside, where the tire/wheel would be. 
plus nothing is set intone, even my current mill build. iv only got the 20' 2x6 beams drilled/tapped for the 2x2 3/8" angle to be bolted to, the 33 1" holes for the leveling bolts, and the 11 bunk cross beams cut. 
when i return from the land of constant rain and hippies, ill order the leveling bolts and trail rail bolts, get the leveling nuts welded on, install the bolts, level the beams, then jig them and start welding in the bunk beams.  
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

mike_belben

Thats probably a $2500 bandsaw.  I think plasma cutters, plasma/waterjet tables and the proliferation of cheap diy CNC has dramatically shrunken the market for vertical bandsaw users.. Meaning it may take a while to find a buyer in that range who doesnt already have one.. But.. Its a serious machine. Lot of floor space.  

Praise The Lord

Southside

So my first thought on that big Peerless is why tear it all apart to just rebuild it? Maybe trim it down a bit, build a carriage, and end up with a vertical saw rather than a horizontal saw. It would have some advantages when dealing with big logs. 
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

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