Hydraulic Lt40 operating tricks

[alpmeadow]

Last season when cutting, I recall some basic problems that I'm sure has been covered in this forum but I can't find them. 2006 lt40 hydraulic gas engine.

1. Clamping somewhat frozen log with and without bark, I clamp the log, and at times it rises up slightly, then pull I down slightly to ensure log sits down flat.  Many times the clamp does not pull it down and rips or slips off the face of the log.  The clamp works well on square edged cants, but the flat face design of the clamp does not bite full contact on the round log surface. Is there a remedy for this?

2. Cutting long cants into 1 by material, when I get to the last few cuts, the tail end of the cant, tends to bow up or down(natural stresses in the tree) or won't sit flat on the deck, as I cut the last few feet since it is clamped only in one spot on one side of the cant.  Flipping it over before I cut is a pain, since the cant then bows up in the middle where I want to clamp.  Putting a weight on it, operating the clamp, removing the weight then starting to cut, is a slow process when I am cutting alone.  Is there a need to setup a second manual clamp at the tail end of the cant or another trick?

3.  Bigger logs with lots of taper.  Wavy cut syndrome.  Cutting into logs toed up at either end, means means cutting 14 to 16 inches wide at one end and 4 or 5 inches wide at the other end. 
A)As I cut slow and steady, I may still get waves due to different cutting widths on the log and the wide throat I must maintain to get through the cut.
B)If I narrow the throat as I cut I still get a slight shift and wavy cut.
C) Unexpected knots, on the opening cut, the engine labors and the bandsaw slows slightly and then accelerates after the knot. Hence it leaves a slight rise and dive at bigger knots. I discover this on the final cut for the cant, as the right side of the cant needs to be cut again to take out the waves. 
Is this a "live with" wavy cut syndrome, or will the experienced mizers laugh at another greenhorn?

Hope the snow leaves soon and I can get the mizer out of hibernation.
Cheers
alpmeadow

[Warren]

Alpmeadow,

The woodmizer folks are just a phone call away.  Things you may choose to try from simple and quick to more time and money

1) Do you have the problem with a new out of the box blade ? Starting with a fresh new blade is the quickest, easiest, cheapest way to eliminate the blade as a problem. For me, when I see big movements around knots, it is typically time to change the blade.

2) Proper tension on the drive belt ?  I still don't understand how a slack drive belt causes a wavy cut or dips, but proper tension on the drive belt will reduce the 'wave".

3) Are your blade guides properly aligned ?  Once upon a time I was having an issue.  The WM rep had me check blade guide alignment.  Surprise, surprise, one side was pointed down, the other up.  Not major deflection.  But enough.

4) Are the rubber belts on the blade wheels worn ?  When they wear, they take a set that pitches the blade down.  For me, this would cause kind of "scooping effect" on wide cuts where the blade would dive in the middle of the log.  this is particularly where I wold see a big bog on the motor as the blade wen to China.

5) Finally, how much set are you running ?  I found out last summer from the WM guys that a blade with too much set causes a problem on wide cuts in harwoods.  Apparently, the extra set creates too much saw dust that spills out of the gullet during the cut and deflects the back edge of the blade up or down.   Since I saw whatever folks drag in from cedar to 2 year old oak, I went to the 4 degree blades.  The reduced hook angle seems to help reduce the wavy cuts in bigger hardwood.  And I don't notice any loss of speed in the cedar.  So I am probably moving to 4 degrees for all around sawing.

Hope something in here helps.  Like I said, the WM folks aer only a phone call away.

Warren

[ARKANSAWYER]

  1  You are clamping to hard.  The clamp is just to hold the log from rolling off the mill.


   2  You should take a few cuts off one face then flip the cant 180 degrees and cut to the deck.  Check the center back stop.  Run a string from the little block in the front to the little block in the back.  The bolt stop and the center stop should be about 1/8 of a inch back from the string and square with it.

   3  On large butt cut hardwood logs try to cut level with the bark.    This will produce a cant that has alot of taper but the boards will be of a higher grade.  The cant can be squared latter in the lower grade wood.  Also wholesalers take boards that are wider at one end then the other so long as the thickness is right.  Some waves are just a part of the cutting and it is why this is called ruff lumber.  Drive belt tension, blade angle, roller adjustment and blade belts all make a differance.

[WH_Conley]

The above replies have about covered everything mechanical.

Something that I do sometimes, especially with long or high stress logs is once i get down to 4 somewhat square faces, I don't worry about the wane, is take cuts alternately from the top and bottom. Then edge the boards with wane. That won't work grade sawing but works for construction lumber. If you are going to do that, don't crowd the blade too much, it can pull the already cut lumber off.

[woodhick]

I was having the "wavy cut" syndrome is some dry white oak I was cutting.  I ordered some of woodmizers 4 degree bands and they made a world of diiference.  I will probably switch to them for all of my hard oak cutting.   A lot of people have said that the 4 degree bands run slower but I did not notice having to slow any more than with the others. 

[alpmeadow]

Much appreciated advice.  I usually run 1.25" blades with 7% angle and run them 2 hours in cedar,  fir and lodgepole pine.  Outside sharpening is good and the blades cut better the second time round.  Our sharpener wants me to try 4% one of these days.  We did check and adjust  the guides once but with only 150 machine hours at the time, it wasn't expected.

Belts, tension, and leveling are good except when I'm lazy or negligent.

When our wood gets stressed and knotty, we pay the price! Is there a tree psychologist around?  A mizer only gets stressed when he's (k)not cutting!

Regarding stressed wood, I was wondering if anyone had any success with some type of additional manual clamping configuration to hold down wood. 
Cheers
alpmeadow

[MartyParsons]

Check Engine Drive belt tension. Turn your log or cant more often, Some types of logs require turning every cut, ( some even need to take a trim cut before cutting the desired thickness) Clamp at the same height as the back supports and use clamp to pull down on your log or cant, but not enough to break the side out of the cant ( usually on the last cut this happens if you are not carefull). Try different hook angles, use the hook angle to saw the hardest part of the log ( Knot) . How many HP do you have? Try a .055 blade 9 degree hook. Make sure sharpner grinds the gullet and you only run the .055 blade 2 hours.
Marty

[ARKANSAWYER]

  Put stressed lumber in the bottom of the pile and that is why the big mills steam their lumber and band them down in bundels.  Cut the bands and up pops the lumber ;D

[Kelvin]

This is the hard part of sawmilling, trouble shooting and trying to keep peak perfomance.  You got good advice about starting with the basics and working through possibilities.  Pine is particularly tough as you go from very soft wood to very hard wood (knots)  softwood wants different blade configurations as the chips expand differently when cut from the log.  More aggresive hook angles and wider set.  Its hard to have one blade perform well in all enviroments. 

A lot depends on your engine power.  A big engine can keep blade speeds up, so blades don't wander, and run more stable, thicker blades.  my Kohler 25hp gas is pretty whimpy so i don't get the life out of my blades the guys with diesels and electric get.  I think slower feed rates monkey up things as well as too fast.  You want a good sharp blade, especially for knotty pine.  Wide cuts also bog down small engines, causing waves but the blade should be stable enough to stay flat through 24" wide cut at right speed.

Do you have debarker?  I'm amazed at how any bark, even clean looking bark will dull blades as grit blows in the wind and gets impregnated into the bark.  Sawing clean faces helps with this.  You need to get good at feeling and seeing the teeth points.  This is the hard evidence, not time on the mill.  Get a magnafying glass and look at the outside set points.  Just like on a chainsaw, but smaller.  THey have to be sharpened square.  Sharpening is easy, setting is not.  Especially with woodmizer double hards i would guess that only woodmizers equipment would make the set real well.  I've tried semi-auto setters and they can't handle the varying force that the double hards require. I've never had luck with outside sharp shops on setting properly. I use a single tooth manual setter and the amount of force to set each tooth within .002 of each other not only varies but is alot harder than any other non hardened blade.  A sharp blade will work okay for awhile, but set really is critical, without it you can't saw.  How does the wave problem compare to new out of the box woodmizers compared to freshly resharpened.  I know you said they were better resharpened, but for how long are they stable?  I get about 200 bd ft of pretty wide sawing on my blades before they slow down, so maybe an hour and a half by myself.  Pull the blades before they are being pushed.  This is where waves come from.  My mill produces no waves if my bands are right.  Any waves? pull the band.  Waves on edges are no biggie, but on the face?  I would kill anyone who hired me to plane lumber that was even slightly wavy as it screws up the planer.  You need pretty tight tolerances.

This is a real aggrevating thing to figure out.  I would constantly be checking blade level with the gauge woodmizer provides with the saw, and making sure the right amount of down pressure is on the outboard bearing.  All critical adjustments on thinner bands like the .043/.045 size  Loose drive belt causes slippage i guess, changing blade speed.  This is bad and produces waves in the same way knots lower band speed and cause dives and whatnot.

You might want a couple of blade profiles for different occasions.  4 degree for 16" plus cuts in the hardest of woods.  9 degree for standard hardwoods, 10degree-12 degree for softer hardwoods and up to pine.  Of course the set varies as well.  I sharpen my own so i just keep 9 degrees with varying set for hardwoods and pine.  Its the best i can do under the circumstances.  Works okay.  Timberwolf i think has a lot of info on blade pitch, set and width on their websites.  I wouldn't fall for their super expensive blades, but some good info.

Your cants shouldn't be moving around that much unless its a squirely species like cottonwood, or a tree with too much stress/lean.  Cants that move around will likely produce lumber that also moves around.  Like other poster said, big companies pack their lumber tight with metal bands and it springs back once tension is off.  This is bad for end user.  Will your buyers appreciate lumber that turns into bannanas off the table saw?  If you are through and through sawing you may be causing the tension in the cant, but the 2 way clamp should pull it flat if its in the 1/8'-1/4" range.  If the hearts are way off center, you will have trouble and so will your customers.  Sometimes its better for firewood.  You can saw some of these by positiioning the curve in a certain direction and sawing across the stress, but i don't think this makes good lumber in the end either.  I'd only use it if i were working with it myself.  Customers will be watching to see how well your lumber performs compared to where ever else they are buying.

Good luck,
kelvin

[alpmeadow]

Great advice!
I have the kohler G28 engine with fuel injection. Good engine for cold starts.  We looked at the diesel, however one of the local guys with 20,000 hours on his misers,  found the dry pine cuts were not good, had excessive band marking and went back to gas.  He determined the diesel having lower rpm, and its engine resonated to the mill cutting at those speeds(dry pine only).  Live and learn I say.
Cheers
alpmeadow

[Brucer]

Hey, alpmeadow. I've got the same model (and age) mill as you do. Saw the same species, as well (I'm guessing by "fir" you mean Douglas-Fir).

1. Sawing frozen softwood logs is a pain. You want barely enough pressure to hold the log in place while you cut. Soon's you get a flat on one side, turn the log and get the flat up against the side stops. For me, it was mostly a matter of getting the "feel" of the clamping pressure.

2. Western Red Cedar is notorious for bending as you saw out the stresses. The smaller the log, the more it moves. The stresses in WRC are about the same as any other log but green cedar is not very stiff. It moves a lot when the stresses become unbalanced from sawing.

For 1" material, square up your cant with the pith centred. Take one board off the top, flip the cant 180 deg, take 2 boards off the top, flip it again, and so on. Usually when you get down to 4 or 5 inches thick, you can clamp it firmly and simply saw down to the bed.

Another way is to saw 1" off the top of your cant, then 1" off the bottom. Unclamp, shift the cant off the bottom board, get rid of the boards, and reclamp the cant. Personally I prefer the cut & turn method.

If you cut too deep on one side, the cant will bow up in the centre (cutting any more on that side will make things worse). Best to flip it right away and saw the other side. I've had some success with weighting the ends of the cant to pull them down (but only with cedar, and only with a "slight" upward bow. As for pulling down the centre, clamp the cant gently, then wack it with a dead-blow hammer. Sometimes the cant will actually stay down ;D. Increase the clamp pressure when it's flat so vibration on the saw doesn't work it loose.

3.
A. Don't cut too slow. This is the biggest mistake I made at first. With sharp blades, properly set, you should be able to push the saw until the engine almost starts to slow down. Knots is the problem here, because they can slow your blade down before you realize it. Wavy cuts are caused by a lot of things - dull teeth, bad set, low tension, blade guides out of alignment, and the blade moving too slow. Folks often miss that last point. That's why belt tension is so important.

B. You mention "slight shift and wavy cut" when you move the blade guide in. Does this mean your blade is marking the wood when you move the blade guide? If it is, you've got an alignment problem with the blade guide arm. I can cut D. Fir up to 18" wide with no problem, just as long as the blade is sharp.

C. If you enter a cut too fast, by the time the engine governer reacts to the change in load, you're already well into the cut. Meanwhile the blade has slowed down briefly and made a wave. I always enter the cut dead slow and then push the speed up to the max.

One last point -- pitch buildup on the blade will pick up sawdust on the top side (it gets pressed into the pitch as the blade goes around the bandwheel). This has the same effect as taking the set off the upper teeth, so your blade will want to dive. This used to cause me a lot of problems with lodgepole pine, and the odd pitchy Douglas-Fir. Lots of lube is the answer. Can't get the pitch off a still-sharp blade? Saw a green cedar log swith it ;D.

So who's sharpening you blades? Are you using Hi Country in Salmon Arm?

[Dave Shepard]

Resonance can come from many things, blade type, tension, sharpeness, feed speed. I would be surprised if those marks couldn't have been overcome with a change in band choice or maintenance. Our electric mill makes some horrible marks with the blades that it came with, even after coming back from ReSharp. When I use the .045s it cuts like butter.


Dave

[alpmeadow]

Hi Brucer
Your story on cedar is very helpful and true, and since I haven't cut for awhile, I find you have to rediscover these tendencies again.  However if I see alot of big knots in the cedar I'm cutting, I slow down through the whole cut.  I do have the debarker, but I did not adjust the belt tensioning right for awhile.

If pitch is a problem I increase water rate, and if I observe the blade tension  increase by itself, I know I may have to stop and clear  sawdust buildup off the belts.  A couple times when I didn't, the pressure increased then decreased as I continued to cut, and the blade broke.  I inspected and found more than one stress fracture on the blade(after only two sharpenings.) 
Roger, a local, sharpens my blades on his self built system, and after this he took slightly more off the gullet to deal with the microscopic fractures that always happen on (.045) on bands after so many revolutions.

So in hindsight, these miser tricks are grouped as behavior modifications needed for the log, the machine, and the operator including:
1.  Know your wood, its stresses and knots etc and if necessary cut more balanced around the pith.
2.  Right bandsaw sharpened with  proper set,  angle for the wood species, its pitchiness, hardness,  and moisture content.
3. I only have 25 band blades right now so don't have enough for set and hook angle options.
4. Get a new operator, the old dog never learns.

Dave, the diesel resonance story was learned third hand through Marv, at Woodmizer Salmon Arm office, they had carefully tested different machines on dry pine very closely to get this conclusion(I can't offer further technical info)
Thanks
Have a Great Day
alpmeadow

[Brucer]

Dave, the diesel resonance story was learned third hand through Marv, at Woodmizer Salmon Arm office, they had carefully tested different machines on dry pine very closely to get this conclusion(I can't offer further technical info)

I seem to recall some discussion about that particular problem on this forum. The standard hydraulic would cut the wood fine, but both the super and the LT70 wouldn't. It drove Marv & company nuts for a while trying to figure it out.