Routine Alignment

[jeepcj779]

  I was doing a routine alignment check yesterday on my LT50. I set the mill up "eyeball" level and started to do the check IAW the manual. When I got to the part where you check the blade height with the guide arm 1/2 in from full in, then 1/2 inch from full out, I measured 1/8 inch higher with the guide arm out (the manual says it should be 1/16 higher with the guide arm out). I checked it again with the same results, then went on with the rest of the checks up to where you check the height of the guide blocks at 15 inches. The manual indicates the inner and outer measurements should be the same, or the outer should be about 1/16 higher. Once again, I measured 1/8 inch difference.
  I thought it odd that after about 17 hours that I would be out of specs already, so I got a level to see how much out of calibration my eyeballs are. End to end I was pretty close, close enough I don't think it would make a difference. Side to side, however, I was out by more than a full bubble. It was getting dark, so I decided to save it for later. I have not gotten to it yet though, so in the mean time, does anyone know if being out-of-level side to side will make a difference on the saw head tilt measurements?
  Also, I searched for videos of the saw head tilt adjustments on the internet and came up empty. There are a few videos from Wood-Mizer on other alignment procedures, but not that one. If anyone knows of a video of the procedure, I would appreciate a link.

[terrifictimbersllc]

Probably not related to not having the bed level side to side.  But get rid of that question by having the mill set up properly either level at both ends or maybe part bubble high on the idle side but both ends the same.

You dont say which side was too high (meaning bed out of level, not the blade  height difference).  I suppose if you jacked up the idle side high enough,  you would reach a balance point where the outside of the head would eventually tip up and teeter back and forth).  :D

1/8" out yes it is more than supposed to be but only 1/16" high. Whether it was in spec originally or not doesnt matter now, anyway that was only as good as the person who adjusted it in the beginning.  

If you like making sure things are perfect then go through the complete alignment step by step.  It is good to do it often enough where you understand it all intuitively. Pays off when you have an "incident" away from home and have to get back to sawing accurately in a hurry.

The height difference (guide wide open) of the blade above the rail inside vs. outside is also affected by whether one of the guide assemblies (drive or idle) has been raised up or down. The correct adjustment in that case would not be to tilt the head.\  For example if something happened that raised the outer guide assembly 1/16" (maybe something is loose and it vibrated up because the roller assembly is always being pushed up by the down pressure) then what began as a perfect setup would now be 1/8" high rather than 1/16" high on the outside.   You would only know this if you took the guides off or relieved the roller down pressure to find out what the tilt is of the free band actually is.  Then restore exactly 1/4" down pressure on each side.   Also when you are measuring blade height you need to maintain blade being level with BGAT tool, otherwise if the blade is tilted up or down across its width this will appear to be blade height when it's not.

The good news in all this is the underlying adjustments of head tilt and bed rail positions are remarkably stable given what the sawmill is subjected to over a year's sawing.  All of my complete alignments to LT40 super and LT70 super over many years seldom resulted in more than 1/16" mostly 1/32" corrections.  Insults to the guide assemblies and guide arm probably cause most of the need for adjustment.

[jeepcj779]

Thanks @terrifictimbersllc. Thw loader side was the high side. I thought that since the blade height (when checking the head tilt) and the bottom of the blade guide were off by the same amount that it was the head tilt that needs to be adjusted. I did not think about the adjustment for down pressure potentially being less than 1/4 being the issue. I will do some more reading about that tonight. I would think that would be the first thing to check when doing an alignment though, because if I adjust the guides for  down pressure, the other measurements will change also. We'll see. I have much to learn.

[Southside]

FWIW I have about 3,500 hours on my two mills and have never adjusted the alignment on either.  They cut flat, square, lumber, so why mess with it is my opinion. 

[terrifictimbersllc]

I didnt catch that.  If the bottom of the blade guide arm fully extended vs. closed is 1/8 higher just like the blade, then both would be fixed by lowering the outside of the head with a quarter turn of the adjustment nuts/bolts which let the head fall down on the outside. That might be what it is.  

It's easy and if everything is perfect after that no reason not to do it. Otherwise if you lowered the roller 1/16 instead of tilting the head 1/16 then when it is closed it would push the blade down on the inside by 1/16.  

It probably doesnt matter what you do to get 1/16 adjustment if everything ends up right. (lightning strike me I'll look out)

But make sure the blade is level widthwise (using the bgat tool) before depending on height measurements of it.

[terrifictimbersllc]

FWIW I have about 3,500 hours on my two mills and have never adjusted the alignment on either.  They cut flat, square, lumber, so why mess with it is my opinion.

I dont understand that.  wear and tear, blade height or tilt at least?  Never set the blade on a cant or run the guide arm into something?

[Southside]

Blade height via the setworks yes, and yes I have smashed a blade onto the cant, running and still. Guide roller has hit knots, etc, the aluminum arm isn't as straight as it once was. 

On my 70 the only thing I have adjusted is the roller arm as it crept up over time. I keep saying that I am going to remove it anyway, not like it helps at all. 

[SawyerTed]

I'd be more concerned with the dimensions on the lumber coming off the mill.  

If the mill is producing consistent lumber that's straight, flat and square.  I wouldn't start adjusting.  My mill has 500 hours and I've checked alignment a couple of times.  The back stops have been adjusted but other alignment hasn't required adjustments.  

[jeepcj779]

  @SawyerTed, I have mostly milled 1x10's and 1x12's so far, with a few 2x4's for pallets. They are square enough for barn siding and pallets. While I have not been checking them for square, I did notice that some of my stickers seem to have a parallelogram look to them, but that didn't matter much since the sides were parallel.
  With all those things in mind, I went though the entire alignment procedure. The blade tilt was off by 1/32nd, which is ok in the book, but I adjusted it to make the front and back measurements the same. I also took about 1/4 turn of tilt out of the head tilt adjustment bolts and went from 1/8th to 1/16th like the spec says. One other thing I had to adjust was the blade reference height. I noticed several times while sawing using pattern mode that my bottom board ended up looking a little thick compared to the ones above it. I assumed at the time I had messed up the settings or stress caused the issue. Turns out the 12" reference was set at 12 1/16th. It is now set to 12" from the bottom of the down-set teeth. 
  I will get the opportunity today to test how the adjustments work out. I am going to saw about 2mbf of SYP I cut down and staged yesterday at my neighbor's house. Thanks for the help.

[richhiway]

Check that the backstops are square to the bed. Don't put to much pressure on the clamp. Also flip the log 180 onto the bed after the first cut.
 Cutting off the bed will give the best accuracy if you require it.
I think outofthewoods has a you tube video on the subject.