OK, I sometimes cut with the sawmill running slightly uphill (an inch or so from end to end), so the carriage tends to stay home when I'm not cutting.

The tracks should both be straight, within whatever tolerance you want your cut. The rail the wheels roll on is more important than the top edge, but being off more than 1/8" I would see as a problem; 1/16" or less is my comfort zone.

The bunks should also be level with each other. I run a string across from the first to the last (only the ones that hold the log, not any that are beyond my cutting range), and set a 9/16" nut under the string at the end two. The string should eyeball about the same height above the rest of the bunks.Check both sides, because the bunks may not be completely parallel.

Next, check your blade. Make certain that both sides of the blade are the same height above the bunks on both sides. Check BOTH ENDS OF THE MILL. It may be that the blade is even with the start position, but when you get to the end, a slight twist may have crept in. If so, try to logically see what of the other measurements may have caused the difference... because one of them is off.

Hey, Jason

Ok.  This is one I've fought with. The following might or might not help, but it's a data point, so here's what I do.  Keep in mind, this is for a static sawbed, mind you it's 28' long, and on a soil yard surface in an area where frost penetrates up to 5', so EVERYTHING needs checking yearly.

1) That first rail needs to be STRAIGHT, and LEVEL.  I use a laser level, and I won't accept more than a 1/32" deviation, because it affects all the rest. Do every bunk.  If any bunk is so far out that it's opposite side is holding it up or down, place a weight on the near end of the bunk.  A concrete block usually is enough.

2) Then level the first and last bunks.  LEVEL. Since a laser is useless, I use a trued bubble level, and I dont accept "between the lines", the space on each side of the bubble to the line must be the same.  Again, downstream actions are impacted if I fudge this.

3) Now I can level intermediate bunks on the second side, but not with a level - I set the level for the beginning-to-end line, then bring all intermediate bunks to the laser line.  Tedious.  This year, I had to go back and raise all other points by 3 turns, after I ran out of turns on one levelling screw.

4) Go back and check 1), then 2).  I've had the sawbed "relax" as part of all of this, and I had to start again.

5) Before (6), clean the wheels of the sawhead.  We're trying to do our best here, so why not?  1/32 of sawdust on the wheel is half our root error, for heaven's sake!

6) So now I have a bed I believe in.  Check the sawblade.  Is it parallel to each and every bunk?  the same distance?  If not, something shifted, or I had a whoopsie moment.  Either way, time for a retry.

6) So it's all good.  Now it's time to set those posts perpendicular to the bunk they're attached to.  Since the bed is true, and true to the saw, your only variable is the post.

7) Now, grab a chunk of scrap log(you did bring one, right?  Every log is valuable, to a customer) and make a 6x6.  Is it uniform in thickness and width, and are the corners square?

This is what I did this spring, after five years of admittedly happenstance sawing.  My results this year were uniformly good, other than two technical issues, one of which was the transition to new blades(see thread about Sabretooth blades).

Keep in mind, this is a static mill, 28' long.  I don't trailer.  You'll have to check with the trailer folk to find out what they do, but I would hope it's at least a subset of the above. 

Finally, remember.  Despite your best efforts, your log is "live wood".  All the levelling in the world won't fix a log with a 1/2" lift in the middle due to internal stresses.  But at least you can explain to the customer what you did, and why, and why his log might not be "perfect". 

Blair

P.S. I've got sidehill oak logs in the 12-16" range in my spring plans, and I know they'll be a disappointment; no matter what I do, a "straight" log off that hillside will give me cants that lift 1/4" or more - in 8'.  It's not the saw, it's my desire to get planks out of logs that should be rocking chair rockers(for me, five years from now).  But it's my trees, and I'll do what I want to.  At worst, I'll turn each cant after every cut, and that will keep the deviations under control.  I just wish I'd known this five years ago, as we planed a third off the thickness of what we cut in our first year.  Fortunately, we cut a lot of 5/4", so 3/4" was salvageable.  Not really germane to your question, but  you're starting out.

Your plan looks good for a stationary, and with that length, I can see why you have to be so careful. Mine is a 12' cut on a mobile mill.

I also found that the supplied legs don't give the support I need; I use those little triangle trailer screw jacks to support it once I level it. Otherwise, when I am working on soft ground, when a log is too unbalanced on the mill, I have to re-level it again, sometimes with the log on the saw. That sucks.

Blair, you've got more good info in that one post than in most books on the subject!  Thanks for taking the time to post it.  Like R.Garrison, I have a portable sawmill, but the "soil" here in southwest Missouri is so rocky, the feet seldom sink more than a few thousandths of an inch, no matter what you put on the mill.  When I set up the mill, I level it front to back, as well as side to side, checking both sides, both ends, and every crossbunk.  To keep the mill from rolling on a windy day, I clamp a pair of vice grips to the track (and oft as not forget to remove them when I start to cut).  Having everything level gives a good reference for other adjustments.  It makes it easy to square the log stops to the track (important for the second slabbing cut), and checking the blade, using a bubble level attached to a magnet to make sure the blade is parallel to the longitudinal, as well as the lateral axis of the mill.  As a final check, I occasionally sight along the tops of the crossbunks to make sure they are straight and parallel.

 

As for the blade coming off the bandwheels, did the log move when you started to cut it?  If not, check your (I mean the blade's) tracking and tension, and double-check on where the blade rides on the rollers.  LM29 owners will be of more help on this issue, but I can certainly sympathize with you.  I've had logs roll while cutting them, and it is no fun getting the blade out!

Thanks, Dave.  It's an honour to receive praise from you!  I posted it because it's a hard-won lesson for me.  No reason others shouldn't have a chance to learn from it.  I've learned a ton of things the easy way on this forum, listening to the experience of others.  Time to payback.

Jason, I've got an ML26, predecessor of the LM29.  Three good ways to throw a blade are:

- as Dave said, have the log clamp loosen or drop completely, and the log rolls 

- blade strikes a hard metal object (could be in the log, could be a post) - human nature is to rebound backwards, and like as not the blade will pull off, which just adds to the misery and cursing.... This also applies to trying to sneak backwards without having hit anything, say to clear a stray chunk of bark from the track ahead of the sawhead (ask me how I know about that one...)

- try to bring the head back down the log at the end of a cut without lifting the blade; you'll either snag a sliver, or catch the blade on a "hump" if the blade has been doing the "dive and crest" that's typical with too low a tension, or wood with a large variation in hardness - like white pine or spruce.  Been there, done that.  Some say they never raise the head and have no problems, but my experience is different.

 

Pulling the blade back out of a cut (usually so you can trim the log to get through it) can also throw a blade.  Even with the blade stopped, tension in the log can close up the kerf and pinch the blade. Plastic logger's wedges to hold the cut open are a big help.  I always lift the blade a half-turn when returning.  Of course that means remembering where you were on the previous cut so you can drop the blade by the appropriate distance for the next one.  Metal strikes and throwing the blade result in horrible noises that would curdle the blood of non-sawyers-- mostly, as Blair says-- coming from the sawyer.  Hopefully, just knowing that we've all been there makes it a little less frustrating.

Speaking of wedges, when I am configuring a log to cut those nice beautiful boards, I get a number of little chunks that were knot lumps, stuff like that. I have learned to set a few of them close by, in case I need to use them as wooden wedges later.

I'm new to this game as well and had a heck of a time getting my lm29 to cut strait without any dips or dooddles. I tried leveling with a bubble level, a line level and even

a transit level. Then Bill gave me this piece of advice " Don't worry about level, as long as its close, just make sure that the blade distance to the crossbunks are the same

at each bunk and at both sides of the bunk" My mill is stationary, but after taking Bill's advice, I am now cutting logs up to 20' with absoulutely no variance from one end

to the middle to the other end. Also way easier than messing around with a level going back and forth adjusting this then that then this again.

Thanks again Bill 

I have a little trolly jack (the kind meant for smooth floors) that is about 30 years old. I use it to lift any sagging spots in the mill when in the field. I then set jackstands, or those little triangle trailer jacks under the ssupport location. I jack a spot, support it, jack another, support it, etc.

 

How do you guys use the LM29? I assume you snap a reference line someplace and line one leg of the 90* beam up with that line and pull from there? For a deck, the reference line is usually the ledger. I guess you would mount the laser to shoot along it and work your rim off of there?Granted, I don't have an LM29, but...we usually use a Topcon RL-H4C to calculate the longest diagonal we can get for squaring because it's so quick to do and is very accurate.

 

 

I generally use a level, starting from where the head sits. I go down one side, eyeballing and trying to get the other side close as I go.

Once I reach the tail end, I then start leveling the other side, and cross each bunk. When I get to the head, I should be able to put a level across and not have any adjustments. If I do, I need to retrace my path, to see where I went wrong.

For my LM29 after the initial level during build per the manual, daily i measure the blade to bunk distance on each bunk and make sure each one is level. Beyond that it doesn't seem to make a difference to my setup (LM29 with 4ft extension on trailer) Every board milled this method had less than 1/16" deviation in thickness

Hi everyone

Phone these place and they'll give you the answers and sell you what you need as well. https://www.cutterschoice.com/en/chainsaw/chainsaw-parts

good info!