LT40 strange out of square problem.

[Dave Shepard]

I've been experiencing a strange out of square problem with my mill. I almost always flip 180° when opening a log, in theory giving me two parallel sides to the cant. Then I flip up 90° and use a framing square off a bed rail to square the cant when making timbers. Whenever my vertical face is square to the bed, and I take a board or slab off the top, I get a square edge. When I have a flat side on the bed rails, and the vertical face is square to the bed, I also get a square top edge. But when I flip the cant a couple of times, it gets out of square eventually. There is no rhyme or reason to it. I checked two of my squares against a big Starrett machinest's square, and also bought a new one for insurance, and they were right on. I've checked my 1/16" tip of the head. Checked all bearings on the head, guide arm, roller guides, spacing of the mast pads and I cannot find anything out of spec. Guide arm is tracking perfectly. Anyone run into this before?

[LeeB]

May be too much clamping force.

[ladylake]

I'd guess it's the 1/16 pull which will vary depending on how hard or soft the wood is and how wide you are cutting.  Steve

[Dave Shepard]

I don't think the clamping force should be a problem. All checks for square are done after clamping. I've never had this problem before, regardless of width or species. The only time I've had a squaring issue is if the 1/16" was not set right.

[Larry]

You might check your moveable guide arm to make sure its not moving the band down (or up) as you decrease the throat opening.

[barbender]

Maybe some slop or wear in the back support pivots, causing them to not be consistent? I'm just guessing.

[Dave Shepard]

Guide arm checked X, Y and Z, all good.

Back supports are good. Also, I'm setting the cant to the bed with a framing square, and not relying on the backstops, although when the mill is cutting right, you can. It's square to the bed before the cut, and after, so it's not being pulled by the force of the saw. The most recent cut is always square. The top will be square to the vertical face, and the vertical face will be square to the bed, meaning the top must be parallel to the bed. But the face against the backstops will not be square to the top, which means that it isn't parallel to the opposite face.

[barbender]

Puzzling, is all I can say.

[Cedarman]

Two things might cause a problem among others.
As you rotate, you might be getting some sawdust left under one side raising the cant slightly.
Another thing is that the cant may be twisting slightly as uneven stresses are released as you saw off material.

[kelLOGg]

Just how much out-of-square are you seeing? A pic of the square on the cant would be helpful.
Bob

[Magicman]

The 1/16" is not necessarily an exact or an engraved in stone measurement.  Your sawmill may be torquing a bit more or less than that amount.  After opening the second face, measure the right against the left sides.  You might use the BGAT or even a yardstick to expand this out so that any difference can be detected and measured.

[mesquite buckeye]

I would definitely ck on the clamping and crud under the cant on the bottom rails. Sometimes after the blade goes into the log the bottom will lift slightly, even if everything looks ok before. We always look under the log anytime we clamp and wipe the rails and pieces of bark chips off the bottom of the cant. If we see light anywhere where the log sits on the rails, there is a problem: rideup, cants flexing from stress, overforce or underforce on the clamp especially with some logs at certain positions. If the bottom sits flat and the saw is cutting flat, all that is left is the log stop adjustments.

[bandmiller2]

Dave, be sure the bed rails are level and well supported by the screw jacks. It doesn't hurt to peek under the cant to check for daylight between cant and rail. Frank C.

[Dave Shepard]

Crud under the cant is not an issue. When I'm cutting timbers, I walk the entire length of the timber checking the bed rails on every turn, no exceptions. Bed rails have been checked for level and support. A necessity with the BX on and not bolted to concrete.

Backstops are not part of the equation. This issue is most present when I have a four sided cant, and the stops are down.

I've checked my squares a couple of different ways, and made proper adjustments to the ones that aren't square anymore. (You fold the tongue around the blade so everyone gets the hint: It's really, really not square anymore!  :D )

Stresses in the log are minimal. I'm sawing white pine, and I have never sawn anything so forgiving. I've split a 15"x15"x47' timber down the middle and it didn't wiggle at all. Nothing. I'm not saying there is never any stress, sometimes splitting a 5"x10"x14' into two 5"x5"s will cause them to bow a little, but for the most part, I'm sawing single boxed heart timbers, often in very clear logs.

1/16" has always worked for me. What is puzzling me is that all specifications are as they have always been after a complete alignment, yet I'm having this strange trouble. When the mill is working properly, you get perfectly square on all four corners timbers. (Hint, if you get a timber that is only square on three corners, adjust square as mentioned above. ;) ) It's almost as if one of the track rollers is fouling up, but I have taken the load off of all the rollers and checked them, and they all feel perfect, they all turn smoothly, no catching or anything. If this problem persists, I think I might change them all out just to eliminate the problem. I'm hesitant to spend the money, as I can't really spare it, but if I can't saw a good timber, then I can't make any money with the mill, either. The mill has 771 hours. Is this in the right hour range to expect a track roller failure? Certainly they can fail at any time, but I didn't think I would see one go with such low hours. The mill head is always tarped when not in use.

I've just had a thought as to eliminating the main mill as the culprit. Tomorrow I'll saw a log on the BX. It will be sort of old school meets new school. Manual clamping and turning with 51 HP CAT and Accuset. Should be weird. ;D

Thanks for all the suggestions.

[Dave Shepard]

To answer one question that I didn't get to. Sometimes the out of square is maybe 1/16" on 8" or 10". I can live with that, especially if there are two opposite corners that are square, although I know the mill is capable of perfectly square timbers time after time. Sometimes the mill is sawing pretty well, and on the last cut throws you a curve ball and it will be 1/4" out. That is a reject if it is a timber for a customer. I can work out of square, but I can't sell them that way. The oddest cut I got was resawing some rejected rafters from one order I had. The rafters were 5"x18". I had a lot of hidden defects in the logs, so I had a lot of rejects that I could cut into something else, or even just blocking. I had one cant that was 8" or 10" thick that I wanted to reduce to 5" thick so I could get a couple of 5"x5" rafters for another project. I cut the cant down to 6", flipped 180° and cut to 5 1/2", then flipped 180° again and cut at 5". This is my way of dealing with what little stresses might be there to keep my cant flat. As usual, I was checking for flatness on the bed. I wasn't checking for square, as all I was after was a wide parallel slab. On the last cut to 5", I immediately saw that the shim cut was tapered left to right. After measuring, I found the slab to be 5" thick at the rail side, and 5 1/4" at the clamp side, with the slab still flat on the bed. I can't explain it. If there was a track roller going bad, I don't think it could just go nuts like that and then go back to behaving. That's too far gone. There are also no signs of odd wear on any of the rollers or the bed rail. ???

[Peter Drouin]

Dave I don't go with the 1/16" thing the cat is heavy. I put the blade right on,  I set it at 12" and make it 12" all the way open . 12" to the tooth tip that turns down to the bed. Set the accuset and go. :D :D

[Dave Shepard]

OK, but that doesn't explain the fact that the 1/16" had always worked for me, and also I am getting a square edge when the timber is flat and square to the mill bed. It's a mystery. :D

[BBTom]

Dave,
You said you have checked all the camlock bearings, but I just want to make certain that you have checked the Bottom ones.  One of those that has a flat spot could cause the problem you are seeing.  Also make certain that one of them is not holding all the weight. 

If they are both good, I am stumped.

[Dave Shepard]

As best I can tell, they are all good. I put a cant hook under the end of the sawhead and lowered it until the weight just came off the bearings. They all turned and I didn't see any flat spots. I'll try it again and inspect all the bearings for flat spots.

Thanks everyone.

[Peter Drouin]

But you said it happed only. When you kept turning and taking wood off. You can be off just a little and it adds up.
When I cut a beam I turn only 90 ° , That's when the square comes out. That's where I adjust it if I have to. The #2 face is where it's all about. :D :D :D

[Magicman]

I do the same Peter.  I can lay the square on the second face opening and adjust if necessary.  (almost never)  From then on, the other three corners will automatically be square.

I rely on the side supports because they can be relied on.

[Dave Shepard]

So on your second face you take the slab off and then check for square from the top to the side against the backstops? My backstops are dead on square, and when working with small cants, they are usually good enough to clamp to and be square to the bed. But working on a 30' long log that is 24" or more on the small end, it's just too much weight to rely on the backstops. I know you can push the backstops out with the two plane clamp on an LT40, and monkeying with a log that weighs two tons or more only exacerbates the problem.

If the mill is working right, flipping 180°gives me two parallel faces and when rotated up, I now have a face that I can square to the bed.

[Magicman]

Dave, my remarks only applied to my situation and I have never sawed a 30' log.  I did not pick up on the fact that you are sawing 30' timbers.  Your market is completely different from mine and obviously a different set of rules apply.

Since you have a bed extension, have you verified that it has not settled or is maybe twisted.

Obviously there is something that you are missing somewhere in your measurements or alignments or else you would not be having a problem.  Maybe back to square one.   :-\

[Peter Drouin]

I take the slab, then 1 or2 boards to get a clean corner then the square. And I do that with 45'ers  :D :D :D 
My back stops are right on too , But I don't trust them, :D :D :D
When I'm cutting beams for a framer, They have to be square. ;D

[5quarter]

Dave...I know you said that clamping is not the problem, but I think it is. It explains all the facets of your trouble. if your backstops are square to the rails, and if the cant is laying flat on all the rails and your blade is running parallel to the rails through the entire cut, you cannot be out of square. When you clamp your cant, it appears to lay flat on the rails, yes? But when you engage the blade and begin sawing, you are putting a lot of lateral force on the cant...esp. with that big cat engine. and the faster you saw, the greater that lateral force becomes. something has changed in the clamping system that it cannot hold some pieces flat to the rails while in the cut. What has changed I have no idea. perhaps the angle of the cleat, perhaps something is bent slightly. But that's definitely a gremlin you need to shoot dead, and quick.

I also agree with Peter...after I open the first face, I rotate 90°. That second cut is the money cut.  ;)

[isawlogs]

I had a similar issue with my mill. It was the out side roller (drive side)  that had an issue. the mounting screws had loosened a tiny bit and would let the roller up a tiny bit, wich caused the out of square issue. I have replaced all the set screws and locking nutsand all is good now.

[AnthonyW]

There is a 5-cut method to square a table saw. The same can be used here to determine how much the mill is off from square.

In reality the first four cuts are the most important. If it is out of square at that point it will remain out of square, if everything on the mill is tight. If there is something loose or flexing, the out of square will get progressively worse. After you make the first two cuts, and the second is using the back stops only, are they square?

I was lucky. I was cutting boards that came off out of square. But they were all out of square by the same amount. A performing the complete alignment, the boards are and cants are nearly perfectly square.

If you were to take a 'scrap' log and filtch the whole thing (no turning) does the problem get progressively worse by the time you get to the bottom? Or do all the boards come out the same dimensions?

[kelLOGg]

Could the band be rising or diving? When I experience cuts of non-uniform thickness I will back up the band to the cut it has just exited to see if the back of the band lines up with the kerf line. When the band starts to get dull I willl see a mis-alignment, usually the band has risen leaving the cant a little thicker on the moveable roller side (entry). This will give me a non-square cant. Just a suggestion based on my experience.
Bob

[bandmiller2]

Only thing I can think of now is a band problem Dave,  you must have tried a different and/or new band. Frank C.

[Dave Shepard]

Dave, my remarks only applied to my situation and I have never sawed a 30' log.  I did not pick up on the fact that you are sawing 30' timbers.  Your market is completely different from mine and obviously a different set of rules apply.

Since you have a bed extension, have you verified that it has not settled or is maybe twisted.

Obviously there is something that you are missing somewhere in your measurements or alignments or else you would not be having a problem.  Maybe back to square one.   :-\

I have checked the BX to the main bed frame, and it is in "wind" (old woodworkers saying). I still have the problem working on short timbers, so I don't think the BX is a problem. I am going to saw a short log on the BX, to try and eliminate any issues with clamping or misalignment on the main frame.

The problem is I don't know if it's a measurement or alignment problem, or some sort of weird bearing issue. Short of replacing all the bearings, I don't know where to look. All measurements are according to the book right now.

Dave...I know you said that clamping is not the problem, but I think it is. It explains all the facets of your trouble. if your backstops are square to the rails, and if the cant is laying flat on all the rails and your blade is running parallel to the rails through the entire cut, you cannot be out of square. When you clamp your cant, it appears to lay flat on the rails, yes? But when you engage the blade and begin sawing, you are putting a lot of lateral force on the cant...esp. with that big cat engine. and the faster you saw, the greater that lateral force becomes. something has changed in the clamping system that it cannot hold some pieces flat to the rails while in the cut. What has changed I have no idea. perhaps the angle of the cleat, perhaps something is bent slightly. But that's definitely a gremlin you need to shoot dead, and quick.

I also agree with Peter...after I open the first face, I rotate 90°. That second cut is the money cut.  ;)

I don't know what could have changed with the clamping system. It's clamping, hard if I want it to, the same as it always has. I've run this mill since new, so it's not a matter of me not knowing the power of the engine.

There is a 5-cut method to square a table saw. The same can be used here to determine how much the mill is off from square.

In reality the first four cuts are the most important. If it is out of square at that point it will remain out of square, if everything on the mill is tight. If there is something loose or flexing, the out of square will get progressively worse. After you make the first two cuts, and the second is using the back stops only, are they square?

I was lucky. I was cutting boards that came off out of square. But they were all out of square by the same amount. A performing the complete alignment, the boards are and cants are nearly perfectly square.

If you were to take a 'scrap' log and filtch the whole thing (no turning) does the problem get progressively worse by the time you get to the bottom? Or do all the boards come out the same dimensions?

I square to the bed at every turn. If the vertical face is not square to the bed, I jack it up with the two plane clamp until it is. I never rely solely on the backstops for a timber cut. Boards, yes, it doesn't matter if the edge of a board is off 1/128" over an inch. :D

Could the band be rising or diving? When I experience cuts of non-uniform thickness I will back up the band to the cut it has just exited to see if the back of the band lines up with the kerf line. When the band starts to get dull I willl see a mis-alignment, usually the band has risen leaving the cant a little thicker on the moveable roller side (entry). This will give me a non-square cant. Just a suggestion based on my experience.
Bob

Only thing I can think of now is a band problem Dave,  you must have tried a different and/or new band. Frank C.

This has been going on over the course of about 25 bands. One new box and 15 ReSharps. My cuts are very good, unless I push the band too far, which I did once and got some waves.

I appreciate all the input. I know it sounds like I'm disputing all of the suggestions, but I guess that is why I'm so stumped. I've tried all of the usual suspects, and don't know what else to try. I'll put in a call to WM when I get a chance and see what they say. They will surely have run into just about any problem there is with an LT40. Thanks.

[OneWithWood]

Dave, when you clamp do you clamp as low on the cant as possible?
I had a similar problem when I would clamp about half the height of the cant.  Lowered the clamp to within a few inches of the bed and things improved.

[Jim_Rogers]

You said it was 5" tall on the rail side and 5 1/4" on the clamp side.

This tells me that the cant is thicker on the clamp side. Which means to me that at one "rolling" it was not up tight to the log uprights/back rests whatever you call them.

For sake of clarity we'll call the bed rails the bottom or the table, the two moving pieces that the log is clamped against the log rests or log uprights.

When I was taught how to saw a log they told me to always put these log rest/uprights all the way up every time. 1) so you don't push your log off the table/bed rails and 2) to make sure your vertical face is flush up against them, every time.

If you cut two opposite faces first then you're right they should be parallel. When you do that check by measuring the two sides of the log. If both sides of an 8" cant are 8" then the sides are truly parallel. If they are not then it's a mill alignment problem. You'll need to adjust something to take out the "gain" of the thick side.

Now, once you have the two sides parallel then you should be able to roll one face up against the log back rest/uprights, and then trim off one of the other two faces. This is when you have to check to make sure that your corner is 90° if it is not after one or two cuts taking off boards or planks then you need to tip your cant a bit more, buy pushing up on it with the log turner while it's being held tight with the clamp. If it is taller on the clamp side, which is what you're saying it is.

After that side is done and it truly square (90°) to one of the parallel faces then the fourth face should come out true.

Lots of times I don't cut the last board off the first face until I come all the way around the cant and back to the beginning again. That way I have one face that I can use to true up the cant.

Sighting the cant to make sure that there is no light between the cant and the log rest/uprights is good from the end of the mill, but sometimes you have to actually walk down there to the log rest/upright and look at it and see if there is a small gap at the top. Sometime you need to push the cant a little to close up this gap.

When I check my log rest/uprights I use two pieces of 1" square tubing 4' long across the bed rails/table. And I set my framing square on them, not on a board or plank made out of wood.
Steel checking steel is the best.

Jim Rogers

[barbender]

I had a bad bearing in the idler sprockets in the lift system once that caused some inconsistencies, I suspect I have another as my head has been "jumpy". Also, what do your mast slide pads look like. I agree, I think you have a bearing problem somewhere.

[drobertson]

I have seen it before, for me it has been cam followers, as good as they seemed, just did not hold through the log.  Bed extensions would be a place to look as well.  jacks, and foundation too.  trusting you have it aligned, a head scratcher, blades have done funny things, alignment, and bearings has to be there in the picture.

[bandmiller2]

Dave, you know as much or more than any of us here no wonder its got you upset. I would put a level on the saw head and slowly run it to the other end wile watching the bubble. I think you'll see the outside of the head dip slightly, could be bearings or track wear. Frank C.

[Dave Shepard]

I talked to Barry at WM today. He didn't have any rare incidents of misalignment to share. I think my next move is to take the track roller bearings off and inspect or replace them. Every other thing has been checked.

[derhntr]

Dave,
I went through the same as you. Could not get it figured out, every thing looked good. When I had the mill service we found the cam follower bearings on the bottom of the rail were loose. When tightened to specs cant were square again

[MReinemann]

I'll get out of square on my lt35hd if I over clamp.  Maybe the stops need to be adjusted.  Mine will flex slightly if I apply to much pressure with the clamp.  Sounds like it's not over clamping though after reading through the posts.
-Matt

[Dave Shepard]

I talked to Jeremy at Hannibal WM a few weeks ago, and he suggested taking the BX off and moving to better ground. The mil was on compacted gravel, with about 4" of smooth 3/4" stone under it. I didn't think it would make much difference, as I had leveled the mill a couple of times with string lines and level since it was put in that location this spring. Well, I've only cut three timbers since moving it, but they have all been square. So, somewhere on the mill something wasn't being supported when the weight of the head and or log was being applied to it. I did do some really big logs on there about the time that the trouble started, but my string line and level checks didn't reveal any problems. I've got a bunch of short sawing coming up, so we'll see how it does. If that's all it was, then I've got to come up with some concrete before I hook up the BX again. The 10"x10" I cut a few minutes ago was absolutely perfect.

[drobertson]

Dave, I have sawn a pile with jacks not solid, and have never seen this,, this said, it is very possible for sure, it has always been the cam followers and or the moveable blade guide arm adjustments. But with this said, things are sometimes weird with logs and clamping, so it could have been a fluke?

[Jim_Rogers]

I'm finding that really hard to believe. I've set up my mill down hill to the end, leaning to the side and up on blocks, and never had a problem with these positions making timbers out of square.

The frame can be "stress" bent, I know because the frost heaved mine more than once. But once you release the frozen down outrigger pads the mill pops back to being level and true, with no permanent damage.

If the location of your mill has caused your timbers to be out of square something is very wrong.

Sawing with a bed extension that is not completely in line with the mill can cause thick and thin timbers. Don't ask me how I know. But never were they out of square, because of the bed extension.

I don't know it just doesn't sound right to me.

Jim Rogers

[Dave Shepard]

I think the issue was that the mill had settled unevenly on some of the jacks, and the bed extension was still in it's original location. I am accepting it as the solution for now, as all the other options have been addressed. All portions of the alignment were perfect. All bearings were functioning flawlessly. The only thing left was improper support. The only change I made was to unhook the BX and move the mill over a few feet and put the legs down on very well compacted gravel. Voila! Cutting square again.

[Peter Drouin]

That's why I have mine on 6" of concrete.


 

What I get is drift of the mill from logs hitting the loader arms :D :D


  

 
See how far the chain is from the mill.
The BX is bolted to the floor, But the mill slides sideways :D :D
There is a piece of steel I'm supposed to put on the other side of the mill . But then I have to take a leg off and reset, So I don't.  :D

[Dave Shepard]

When you get your new LT70WideHead with the electric motor, don't forget to order the stationary legs. It will never move then. Unless you ram it with John in high gear. :D

The mill was first setup on concrete. I hope it will be again soon. This slab was 20'x104'.  ;D



 

[ladylake]

Any mill made will flex and twist if not supported good by jacks or good blocking if stationary resulting in all sorts of problems.  There was just a thread of a TK mill cutting uneven cants which turned out to be too much jack support in the middle.  Steve

[bandmiller2]

Seems with all mill problems its something simple, we all seem to start at the most complex and work back to the simple fix. Glad you found it Dave. Frank C.

[Klicker]

Have you checked your clamp. I had a problem once and  my clamp was lifting the can't about 3/8 of an inch when I clamped it tight  I had bent something and it took a while to figure it out. Rod

[backwoods sawyer]

I had a problem once and my clamp was lifting the can't about 3/8 of an inch when I clamped it tight  I had bent something and it took a while to figure it out. Rod

When I got my mill it was doing the same thing, what I found was the socket the pivot arm sits in was warn so that when clamping the bottom of the cant would catch the 1/2" stops and rock up to meet the stop. Added a thick washer to bring the dogs out flush with the stops. 
If you see the out of sqaure issue again check that the dogs are flush with the stops and that the two adjustable stops match the fixed stops.
Nothing more frustrating then a mill not cutting square.