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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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thecfarm

MikeySP,Thank You for serving our country.
Welcome to the forum.
I have a Thomas mill. I had them build it so I could cut a 20 foot log. I never have yet. But little did I know how much easier it is to load a 16 foot log onto a mill that is set up to cut 20 feet. The mill gives me four feet to play with,not 6 inches. It also allows me to get the head out of the way too. Just a thought.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Crusarius

Cfarm is absolutely right about the length. I made mine 24' with the expectation of doing 20' cuts eventually. The truth was the steel came in 24's lengths so I decided to keep them that length. But I also did not want to limit myself.

as for why I want to build the LT15 wide copy, every time I have played with one it felt amazing. everything moved real smooth, had a nice wide cut that my mill will eventually get modified to. from what I could see the lt15 wide should be easy to adjust for true. My biggest complaint with it is the cheezy bed they use. but they were intended to be lightweight and portable but they do not offer a trailer package for it. I would love to buy just the head and carriage and build the rest.

MikeySP

I have added the extra length for log space to my notes.

Crusarius, I am indeed intrigued by your commentary about the LT15 being so smooth. What seems to be the key? Is this more because you have a manual w mill and would be null if it were a power feed, power raise lower? What seems to be the key from your perspective? This may unlock some design philosophy. 

Crusarius

they have a gas charged cylinder in the mast to assist with raising the head. the crank is very easy to turn and locks in I think at 1/4" increments. it rolls on the track effortlessly.

All items mine needs work on :) I do have power raise lower but with the acme threaded rod it takes alot to raise it. I think I am going to try to add a garage door spring and see if that helps.

it is still a cantilever head design with 4 post carriage. on my carriage I did 2 post and I think that was a mistake. I feel I get twisting in the carriage making it harder to push. Also my guides are metal sleeves on metal masts so the bearing used on the LT15 roll so much nicer and hold it tight where mine is sloppy and does wiggle around. it does not seem to effect the cut though.

I may think of other things as the day goes on.

MikeySP

Well, it turned out I have two friends from Church that own substantial sawmills: A 15-20 year old Cooks AC-36 w/50hp perkins diesel and another with older LT40HD. 

I just visited the Cooks owner and spent an hour to discuss and take a ton of photos for analysis. 

I knew they owned mills, but because they didn't make any money with them, I assumed they were little push mills. The Cooks owner said he couldn't compete with the local mennonite or ammish sawyers who will saw if you bring logs for about .20 a BD FT. I asked if he could do 2000 BD FT a day and he said no problem, but that stuff breaks pretty regularly from neglect and being weather beaten for so many years, especially hydraulic hoses. He also said he doesn't have the business sense side. Doesn't market, etc...

The machine is pretty serious, but man that thing had a ton of hydraulic hoses. I wonder who makes a more simplistic designed mill and still has the capability?  I plan to look at the LT40HD, but the owner was at the Cooks Owner's house working. 




Crusarius

you can get electric hydraulic pumps and place them at each location but that will get very costly. Would still need short hoses.

I would think just finding a way to run the hydraulic lines so they are out of the weather would improve their lifespan exponentially. can also run hard piping to fixed items with short rubber hose to connect them.

hmm keep giving myself ideas :)

Ljohnsaw

Quote from: MikeySP on October 04, 2018, 02:27:54 PMWell, it turned out I have two friends from Church that own substantial sawmills
Do either of them sound like they want to sell?  Maybe that would be the easier route - use their mill as a base to improve upon from all the ideas here!
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Roland

The first thing I would do is decide what length  blade you want to use. Then pick out the size wheels you want to use. With those items layed out on your garage floor you can now start designing.
Very easy and cost efficient
Sketch up a plan with measurements and just do it.
Adopt the pace of nature her secret is patience.
RWE

Southside

That is significant competition at a bottom dollar price point. You really need to consider that in your plan. 

Perhaps there is a market in drying and planning wood if nobody is doing that in the area. 
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

PC-Urban-Sawyer

Will YOU be able to saw logs to lumber for $.20 a board foot? (and don't cheat and say your labor is free...) If the answer is no, you really need to reconsider your business model and get the Amish to saw for you at those prices...

Herb

mike_belben

Go meet the amish, tell them youre going to make a go of the sawing business and dont want to compete with them in any way.  Ask what their specialty is, so you can avoid it, and what they refuse to do, so you can go after it.  

Theyll appreciate you being a straight shooter and may be a help in the future.  You can each refer customers to the other.  I have never had anyone give me a bad response to this sort of inquiry.  
Praise The Lord

MikeySP

Much to consider. I have been thinking what I can do differently. Also at the .20 rate, that is you bringing the logs to him. Still cheap.

I did read the entire 50 page thread by @kbeitz  and his build. That man knows how stuff works.  While not the machine I want to build, it was interesting. http://forestryforum.com/board/index.php?topic=82853.msg1264270#msg1264270

The guy with AC36 is planning to sell it in a couple months after his house is finished. $23K. I will not even countenance spending that, though that perkins 50HP diesel sure is nice. 

I am looking forward to seeing the older LT40HD and how that cantelever works as well as the apparent lack of a million hydraulic hoses. 

Hilltop366

Quote from: MikeySP on October 06, 2018, 05:54:46 AMthe apparent lack of a million hydraulic hoses.


It has hoses and wires and electric motors and switches...... there is no free lunch. If you want to stand over here and have things happen over there it going to have something.

MikeySP

I understand, just looking for the most simple solutions. Budget and time to fabricate are huge factors for me.  

Hilltop366

I figured you did, Pardon me if I sounded abrupt it was not my intention.

JB Griffin

Quote from: Hilltop366 on October 06, 2018, 08:38:59 AM
Quote from: MikeySP on October 06, 2018, 05:54:46 AMthe apparent lack of a million hydraulic hoses.


It has hoses and wires and electric motors and switches...... there is no free lunch. If you want to stand over here and have things happen over there it going to have something.


Oh does it ever, and you forgot the best part,.............  proprietary circut boards and other things that no local store will ever have and enough wire to wire a small house.

I can go to town and get most any hyd hose fixed and be back in a hour or two, not so with said electrical stuff.

Plus hyd are WAY easier for me to troubleshoot than angry pixies.
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.

MikeySP

JB Griffin, I like your pointed comments. I have made note of every comment you have made in my keep for later file. Very practical and thoughtful. Now if I do use electrical anything (Feed, up/down, etc..) it would be non propriatory. It would be cannibalizing another technology such as a mobility scooter, etc... so that would not necessarily be a problem. However, if I have hydraulics for my log turner for example, I am already set with a pump and hydraulic system. Adding another valve, lines, and motor is not much more. Yet it seems woodmizer does mix and match. Not sure why?? How do you control height settings with hydraulics? For example, if I want 1" boards, do I have to eyeball it, or is there a auto stop feature when the blade gets to the correct down position? Seems having an auto stop feature would make for some great consistency and speed.

Thanks. 

-Mike

charles mann

Quote from: MikeySP on October 09, 2018, 10:53:28 PMHow do you control height settings with hydraulics? For example, if I want 1" boards, do I have to eyeball it, or is there a auto stop feature when the blade gets to the correct down position? Seems having an auto stop feature would make for some great consistency and speed.

Thanks.

-Mike
similar way the accuset sys works, sending a signal to the electric motor to stop at "X" height, the same signal could be sent to an electric solenoid to close the hydraulic valve, as long as you are not over riding the solenoid by holding down on the lever. you would have to figure out HOW to build the resistor rod and write the code for the sensor to read the resistance along the length of the rod. we use something similar in our fuel cells on the chinook. we have thermistor and a signal processor that reads the changes in fuel  "pressure" against the resistor tube. we have a similar function for our internal tank to read water level by elec resistance along the rod as the metal float moves up or down the rod, changing the resistance and the processor converts the elec resistance into "X" gallons of water. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Southside

Mike -

The measuring of the 1" - or whatever thickness you want - board can be done with an encoder.  Basically it counts the number of revolutions a known diameter wheel makes as the head travels up and down, and it converts that into a distance traveled as the encoder knows the circumference of the wheel.  There is another way that uses a rod and ring arrangement but for the life of me I can't remember what those are called as it's been at least a decade since I last was around one.  

Either system will communicate the value it has generated from traveling back to a PLC which will cut off the driving motor when the value you have entered is reached - weather that be by closing an electric over hydraulic valve or by opening a relay which cuts out an electric motor.  This is what a "set works" does.  Without that feature yes you need to read a scale and indicator of some sort and stop at the desired height change.     
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

Southside

Thanks Charles - you explained what I was fumbling around to try and say, guess we posted at about the same time.  
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

MikeySP

I forgot about solenoid controlled hydraulic valves. :) Thank you both for chiming in and helping me understand that. To your knowledge, has anyone done a thread of a DIY version of this with details?


Crusarius

I dunno if you are familiar with arduino or not. But that has lots of capability. one of these days I will make an arduino setworks for my mill. It would be nice to be able to set a home position and tell it to go there while I go load the next log. and then tell it I want to cut 5/4 and hit go. Let it move down 5/4 then make my cut and repeat.


mike_belben

Do not discount air power especially if you are stationary.  Commercial mills seem to use air for quite a bit of setwork function.  You can make an air cylinder do just about anything you want with the controls that are available today using pilot valves, pressure valving, speed controlled mufflers and so forth.   SMC makes anything you can imagine and its cheap on ebay from MRO used surplus vendors.  Plus no hydraulic lines, just vinyl tubing and pushlocks, change them out in two seconds.  

Air motors do exist but are pretty hungry for air and not terribly strong.  I think a 24vdc wheelchair motor is a more efficient choice there.   To use air in a mobile application off the mill,  york 210 AC compressor clutch and old propane tank is plenty to run cylinders for raising backstops, clamping logs, raising a head to clear log for carriage return. The cool thing is you can just keep adding more and more features.. The supply fluid is just vented out to atmosphere so there is no need for worrying about valve center or return lines or cooling or filtration.   Air can be run to an air over hydraulic but theyre a bit hungry too, though it would work for a turner i think.   de-sta-co made some of the best air over hydraulic pumps, very simple.  Now the chinese jacks all have that option.

Chinese ATV winches and reversing contactors is another option.  Surplus center had the contactors pretty cheap.  It wouldnt be hard to put a capstan drum on your cardiage and have a cable tensioned down the bed with adjustable spring loaded tension.  You want slippage when things collide.  A CNC crash is quite a sight but i wouldnt wanna foot the bill.

For stationary or if youll be using a generator on a mobile, dayton made very good 90vdc reversible motors with fwd N reverse and infinitely variable speed control. Theyre 110AC plug in jobs. We had quite a few old tapping heads built from these. The chinese make cheap linear rails and bearings and ball screws now, easy to find.  Hiwin is a common cheap brand,  THK, thompson and SKF are good ones. "Linear stage" is a good search term too for finding all sorts of tagged keyworded parts cheap.

I dont think the great outdoors is a good place for servos, stepper motors, drives, encoders, proxes etc.  Theyre hard enough to maintain inside.

One more thought, ifnyou need hydraulics there is nothing that says you cant have two engines, one for the saw and one for the turner, clamp and maybe even live deck system. Heck why not a greenchain for outbound lumber? A 13hp motor with a 3gpm pump at 2000 psi will run a backhoe at about the normal speed youd dig with and theyre fairly affordable, sub $600 new. Itll convey and flip logs no doubt. You could build your carriage with an operator seat so that you ride the carriage while sawing then when returned home you are in reach of a stationary control panel for log handling.  Would save a lot of walking and no need to figure out a cable carrier and have the saw head cluttered with controls.  Put a beach umbrella and beer holster on the seat, be like a vacation.

For measuring, guys who use linear lift systems like winch cable or chain seem to have linear tapes stuck on with adjustable pointers, kbeitz did a great one.  If your lift uses lead screws then you can put a wide faced wheel with numbers and pointer on the input shaft of your right angle worm gear box. Old circle mill setworks tend to use this.  Look up cross sawmill in georgia on youtube, hes got one on his monster home made bandmill. Boston Gear is a good worm manufacturer. I got many from scrap yard.
Praise The Lord

mike_belben

I have been meaning to critique some basic design elements of my mill for a while but my internet connection stinks and my uploads always failed.  Heres a handful of pics at various angles so you can hopefully see what im talking about.

Its 100% junkpile stuff, zero dollars spent.  I really needed to clean up an area of the yard piled with logs so i could start filling there, and it seemed better to just make rough lumber before they rot. Knock out two jobs at once. Made most of it in a day on a whim with very little thought. 













So part 1 is material weight and rigidity.  To get rigid from light, material structure is critical.  Torsion (twist resistance) is carried best by round tubes. Wall thickness doesnt matter nearly as much as diameter, which youll note pretty quickly in semi truck driveshafts.  5" diameter fairly thinwall tubes transfer 2000 ft lbs.   If you made the letter "H" entirely frame 2"angle iron or flat strip and lifted just one corner the whole thing would twist under its own weight.  Make it from 2" round tube same thickness and itll be totally rigid.  

My bed started as a ladder for an alaskan mill.  It was all streetsign post and super flimsy so i welded in two scraps of exhaust pipe to torsion the rails together. it then stayed flat, i could carry it to the woods one handed.  I went back to the welding table with 2 pieces of 4 inch C channel then spaced the track off the table and welded it together so the channels touched the rails and the exh pipe.  The channels hold the weight of the log, the rails only carry the saw.  The coated conduit between the channel risers keeps them from rotating out of plane with each other and the 1" barstock keeps the log above the exhaust pipe which wasnt very flat or true.  So logs and lumber are still sitting on a surface that my welding table ensured were true, even using junky twisty material.   The barstock is square to the flat side of the streetsign. Good enough.

Now on to the mistake i made.  It was too easy to make my backstops bolt to the streetsign and utilize the holes all along them and that they were 90* to the log deck.  But when you add it a cam clamp at 12" of leverage, the street sign bows out badly.  Its a great material, but it cant handle torsion.  I really needed to put the backstop and the clamp both on the yellow pipe (which is 1-5/8 handrail with ready rail floating on each for the clamps) because it is much much better suited to resist the load of clamping a log.  

So that little booboo makes it where i cant clamp a log up high very tightly.  If i open the saw up WOT and dig in hard, the log will vibrate and the clamps will often drop, especially if im clamping the underbelly of a round side.  If i clamp tighter the rail bends out and im not cutting square to the bed.  So log cutting is slow.  

When im down to a square cant, i flip my backstops upside down so that they only stand about 1.5" proud and apply the clamps down low, much tighter.  Bending the rails, slipping clamps and vibrating log issues all go away.  But if i go too hard the entire rig will vibrate.  Hence my commentary on mass.  In machining, you can only get a quality finish as quickly as the machines' hp, weight and rigidity allow.  Bolt a big fast motor on a light machine and youll get a bad cut from flex.  Reinforce to eliminate flex and you get the entire machine shaking, needs mass.  So it all plays together.  You can only cut as fast as your machine parameters allow.

Next issue that i didnt foresee is clamps.  I dont think i like cams.  A clamp has to work well on 2 totally different products.  A log, and a piece of lumber.  If its an old salvage log with rotten bark and punky sapwood, youll need a really large, mean cam to bite way in.  That punky wood collapses from vibration and you have to keep resetting your dogs, theyll fall out.  Now when you get a nice solid cant to start working down you cant really use that mean dog, itll tear up the wood and it leaves a blue stain in red oak.  Its fine for barn wood but cabinet grade stuff cant have that.  I put one smooth and one gnarly side to my dog for now but i think ill switch to pointed screw jacks eventually.  Probably use wood scraps to prevent the damage and stain on nice cants.  

Anyhow.. Those are the things ive discovered so far from doing it wrong.  The concepts are universal and scale in size, from dinky toys like mine to big mills.  Mass and rigidity are critical componets to producing good, fast cuts. 

Praise The Lord

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