Newbie introduction

[IowaDave]

Hi All!

IowaDave here... Dave... in Iowa...

I'm a total newbie to sawmills and milling... I kinda 'fell into' this situation as a result of helping a friend rehab an old house... he's a fine hand-chisel/plane type fancy woodworker.  If it needs to be precisely fit, finished, and beautiful, he's the guy.

I, on the other hand, am a 'big stuff' guy.  If it weighs over several tons, requires something large and loud to accomplish, involves a very large mess, heavy equipment, a crane, backhoe, forklift, if it requires cutting and welding, ferrous or non-ferrous to 0.0001", or involves interface circuitry to a microprocessor, uses radio frequency energy, common motor fuels, hydraulic hose, encoders, ballscrews, multi-row chains or toothed belts... that's my realm.

So a friend of mine passed away last winter.  I was called upon to assist in sorting things out, and buried in the back of a building was the Wood-Mizer LT40HD he purchased just around new year's day of 2000.  He bought it for a specific task-  Cut up 70ft long bridge timbers 12x24" into smaller pieces to build new boat docks for his marina.  They ran it exactly 140 hours from January 7th through 22nd.  They completed the build, then got on a plane that deployed his unit to the Middle East for two years.

25 years later, I pulled it out of the back of the shed, wrestled everything into a transportable state, fitted a new set of wheels and tires, and towed it 300 miles to my farm.

I spent about three weeks of evenings getting everything un-stuck, pulled all the covers and shrouds, removed a dozen mice nests, a birds nest, lots of mud-dauber nests, cleaned out the air filter housing and carb, changed the engine oil and filter, removed and discarded the (cracked and broken, but bottom coated-with-shellac-sludge) fuel tank... never found the water tank, so I made new ones for each... cleaned out the blade lube sprayers, line, and pump... found a big solenoid by the battery totally welded-seized from being saturated in two decades of mouse urine, so all new cables, and (having no solenoid) replaced it with a marine-type battery safety switch.

Had a few interesting initial finds:

The main foreward/reverse drive did not function.  The belt was hanging on the side of the battery box with a zip-tie...  Motor was a little sticky from sitting, I pulled it apart, scrubbed everything out good, rubbed a little corrosion off the commutator, cleaned up and lubed the bearings, put it back together, and it'd run in reverse, but not forward. <shrug>

I found one hydraulic hose... for the front toe-board extension side... fitting broken off.  Looks like the hose got snagged.  Fitting remains was jammed in the hose-side too tight to back out, so had a new hose made at the shop down the hill... after that, all the hydraulics worked fine.

After checking all the bearings (replacing a rotted-away clear hose and refilling the submerged oil bearing shell on the drive journal) and a few testing spin-ups, I gave it a test-cut through an old pine landscape timber (checking first for nails or screws).  I had to push it by hand, but it made the cut... the blade DID want to drift DOWN really bad.  After finishing, I was cycling the functions, and had the blade-guide chain break.

I had my local shop make up a replacement blade, which cut beautifully.  I dug out a new length of #25 chain and a master link, cussed the blade guide drive geometry for a bit, 'till I finally got that back together... I scrubbed the running surface with some ScotchBrite, then applied some wax lubricant, and it works mostly fine now.. every once'n a while, it'll stick, if I cycle it back and forth, it'll move again.

[taylorsmissbeehaven]

Sounds like a true score! What are you gonna do with this saw? Got logs? Just having fun? Sawmills are an addiction. keep us posted!

[IowaDave]

So the next part to tackle, was the drive.

After some searching, downloading a few different (mostly wrong, but close enough) docs, I found the horizontal axis drive circuit - a diagram that seemed to match the drum switch connections, and a service bulletin about the PWM drive system for the PMDC motor.  In reverse, the drum switch sends full 12vdc through the PMDC motor in one polarity (for reverse, at full speed), and.  The motor drive major electronics are all located on the back panel of the control box, so disconnect 3 large, one small, and three wires to the speed control pot, and the bulk of the works carried into my radio shop for some investigation.

I pulled out my multimeter, looked up the JDEC part number on the primary MOSFETS.  There's an array of FZ44NS mosfets on a circuit board, all the sources and drains tied together (source goes to system ground, Drains go to the drum switch's - terminal in forward).  Each MOSFET's GATE terminal has a 15 ohm SMD resistor, all tied together, and the whole line is shunted to ground with a 10 SMD resistor.  I did a typical forward/reverse test on the junctions of each MOSFET, and they all passed fine.  I noted that the MOSFET board has pads on the circuit board for a suppressor (A Metal Oxide Varistor, probably), but there was none present.

I DID find the ultimate culprit.  There's a little encapsulated circuit board in the back, has some diagnostic LEDs, and three wires going up to a potentiometer on the front panel.  When I put it all back up to test, I noted that this little board had a fault light that illuminated as soon as I put it in FORWARD.

I verified that the MOSFET drive deck was functioning by applying 12v to the GATE terminal... the drive motor sprang to life.  I put the belt on, and it moved the carriage with deft authority.

I did some more reading, and made some phone calls.  My first call was to my friend's father, who although suffering the ravages of age, did note to me that the drive system failed about halfway through their task, on a Sunday afternoon in January 2000... so they disengaged the belt and just finished the job by pushing by hand.  After pushing it into the barn, they totally forgot about the drive failure...

Anyway, I found that this board had a few revisions (over two decades, I would expect that there'd be SOME revisions, at the very least, changes in parts to suit component availability and technology changes)... but it didn't seem like there was anything, aside from the addition of a couple suppressors to the external wiring... that was done to prevent whatever failure was killing this precious little board.

Now, I DID go looking through the web for others' experiences, and I see that my circumstance isn't an isolated thing.

I don't like things that fail, and when OEM things fail, but there's no significant change noted in the part or bulletin, that suggests to me that the replacement part will be no less likely to suffer whatever condemned the first.

It doesn't take much engineering to recongnize that this board's function is to generate a Pulse Width Modulation signal to vary the control current/voltage relationship feeding the PMDC motor... it's actually a very low-tech concept, and it doesn't take a several-hundred-dollar magic module to make that PWM signal.  I happened to have a couple signal generators capable of many common control signals, including 0-120vdc, 4-20mA, variable frequency square, triangle, and sine waves, and also, the basic PWM.  I carried it out to the driveway, hooked it directly to the GATE terminal (and ground), dialed up 12v, and varied the PWM from 35-90%, and that drive worked dandy.

I happened to have some MKS OSC1.0 stepper/PWM boards in my shop for testing drive mechanism prototypes.  Usually I use them to abuse stepper motors for a week-at-a-time, but I moved ther jumpers to PWM mode, connected it up like my test set was, connected 12v to the small red wire, and mounted the OSCv1.0's potentiometer right in the hole where the original Bourns Clarostat potentiometer WAS.  Even used the same knob.

It works like a champ...  and it was eight bucks...

So now I've got a 24" x 90" Black Walnut log on the bed, awaiting it's chance to become pieces of flat, wet stuff.

Now I need a drying system.  My buddy Mike has a bit more Black Walnut trim to make for his project-house.

[IowaDave]

Sounds like a true score! What are you gonna do with this saw? Got logs? Just having fun? Sawmills are an addiction. keep us posted!

Hi Taylor!

Well, like I said... I kinda 'fell into' this.

Bein' the "big stuff" guy, rescuing logs from storm or emergency tree work is easy for me, and I hate to see good materials get wasted to rot or firewood, when they could be fine furnature, musical instruments, boats, or luxury trim.  Since I can make the 'big stuff' happen, my expectation is that if I can get rescue logs cut, dried, and available to local woodworkers, even if I just 'break even', I'll still have capacity to cut building materials for my own projects.

I've got a substantial workshop structure to build... it'll have steel framing, but there's plenty of lumber needed.  i've got an old dairy barn that needs replacement lumber... and I've got a '24 Ford Model TT truck that needs a body... and I have something unique in mind that one wouldn't find in a common 'kit' form... so that means I need special-cut wood.  All I hafta do, is get appropriately sized raw materials, and drive the truck chassis down to his shop, we'll cut and assemble the body pieces right in his work bay.

The opportunity cost to acquire this sawmill was low enough, that simply having the capacity to turn a log into lumber pays for itself.  I expect that, as I use the mill, and as I learn more about the complexity of working with biologically-formed cellulose structures, I'll have enough proficiency to be fairly effective and efficient, such that I can help people around me whose penchance and aversions for working with those materials find me to be an economical source of work-stock... and at the same time, I hope that local treeworkers will call upon me to help recapture what tree value would otherwise be lost for the sake of commerical operations expedience.

[Magicman]

Welcome IowaDave to the Forestry Forum.  Your sawmill recovery journey was a nice read and I send top marks for your success.   

It will now be nice to see and hear about your sawing.  

[Texas Ranger]

Welcome aboard, IowaDave

[barbender]

Hello Dave! I see already that your electronics knowledge will be a nice addition to the Forum! 

[thecfarm]

You will fit right in around here.
Now get yourself a cant dog or peavey from Logrite, sponsor on here and made in the USA and you will be ready for sawing!!!

[customsawyer]

Welcome to the forum. I would like a few more details. Is the mill a standard LT40 or a LT40 super? In other words, does it have one hydraulic pump or two. What engine is on it?
Great score and find on your part. Sounds like the mill found the right person, or the right person found the mill.  

[Nebraska]

Welcome, what part of Iowa do you make your home?

[jpassardi]

Welcome to the Forum & congrats on a great find. This is the place to come to for no BS info.

[IowaDave]

Thank you for the welcomes!

Yeah, I need a peavy AND a cant dog... and some kind of ice-tong-type dragger on short chain to pull logs with my tractor.  I'm also gonna recycle a piece of old nylon truck strap, sew it into some sort of a draw lanyard that I can drop on the ground just off the lift arms, and toss over the head of the log clamp or turner, to use the hydraulics to pull the beasts up onto the lift arms...

I'm on the east coast of Iowa... about a mile from the Mississippi River, not far from I-80... and that's kinda relevant to how I got to this circumstance.  A dozen years ago or so, we had a derecho come through... it mowed off about a 300 mile path of big trees.  A gentleman up the river 30 miles or so had some riverbottom timber land loaded with old-growth Black Walnut, that storm took a BUNCH of them down.  Rather than let them rot, he bought a manual-op sawmill, and started cutting them up, dragging 'em out, and milling them into slabs.  When we got to the point that my pal's house project was ready for hardwood, we bought all the remaining slabs we could... but we were a bit short... and we can't reach the old feller upriver anymore...

This one has just one hydraulic unit, in a big box up on the tongue.  There's a contact brush set that connects the carriage (25hp Kohler V-twin btw) and it's charging system (small alternator) to power the hydraulics.  There USED to be a big solenoid to cut off power through the brushes anytime the key was off, but as I noted above, that solenoid was seized, and I had an extra marine-type battery switch, so it got a manual switch instead.  I've got some modifications/improvement ideas for the machine, some of them revolve around the power situation... I'll note 'em soon.

As for being the right person<->machine, well, the circumstances are both whimsical and rough.  The original purchaser was one of my college roommates, he was 3rd generation running a family business in Minnesota, and basically every year since college (decades ago), I'd make a spring and fall trip up to help him with the season-change.  During his deployment, I made the trip to help his dad.  This spring, I made the trip up to help his brother, and his widow, as he passed away from congestive heart failure just a few days after Christmas.  I never realized he had a sawmill in there, it just happened to be behind a couple machines we had to pull out.  It was clearly in need of some elbow grease, but what it needed worse, was a job to do.  I needed it kinda like I need another hole in my head, but between my friends' needs for workshop project material, and my building projects, it seemed to be a sensible piece of a solution puzzle.  Could it have found me?  Perhaps.  Perhaps it was silently 'stalking' me...  machines do that.

[Old Greenhorn]

Welcome!
 You want to avoid dragging logs it at all possible and keep that dirt out, it kills blades. Got forks? Also, search the forum for "Magic Hook" and you will find a very handy and simple device you can make in a few minutes.
 Now you need to do some reading here on how to read and mill a log. There are a couple of recent and active threads regarding just that, but a ton of others going into great detail. Also watch YellowHammers videos, he's the man. Blade choices and alignment are critical little issues you want to get an understanding of up front.
 Enjoy the ride and welcome aboard the train.

[Magicman]

Actually the Magic Hook is for rolling logs.  You need tongs for skidding.  You will find them on the Logrite site as well as the Cant Hooks.  Logrite

[Old Greenhorn]

........ I'm also gonna recycle a piece of old nylon truck strap, sew it into some sort of a draw lanyard that I can drop on the ground just off the lift arms, and toss over the head of the log clamp or turner, to use the hydraulics to pull the beasts up onto the lift arms........

Yes, Lynn, but I was referring to hic comment quoted above which a magic hook will help with. If he has an FEL, your double log hooks on a chain might work well for him too to lift and move those logs.

[dgdrls]

Welcome aboard @IowaDave 

lots of experience and fine people here,

Good luck with your mill.

D

[Tom K]

Welcome aboard, glad to have ya.

My only comment pertains to your first logs. I would try to find some low value logs to start out with. Until you learn to read the logs and work the mill the possibility of milling "designer firewood" is pretty strong. I would try to start out with something other then high dollar walnut.

[GAB]

Welcome aboard, glad to have ya.

My only comment pertains to your first logs. I would try to find some low value logs to start out with. Until you learn to read the logs and work the mill the possibility of milling "designer firewood" is pretty strong. I would try to start out with something other then high dollar walnut.

Poplar, cottonwood, and very knotty pine logs are good candidates to start with.
Education is expensive and a sawmill will introduce to some of that expensive education.
If you take the time to view, at least twice, Hobby Hardwood Alabama videos it could reduce your educational expenses.
GAB