The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: Jim_Rogers on January 02, 2010, 03:56:41 PM

Title: Woodmizer LT40 blade alignment questions
Post by: Jim_Rogers on January 02, 2010, 03:56:41 PM
Ok, so here's the history:
A while back a friend of mine who owns a 1995 or so LT40HD with a Diesel engine hired me to run his saw for a custom sawing job he lined up. He was going to be there and run his edger while I was running his saw.

During this job we/I noticed that the blade guide roller, the inner one closest to the drive wheel was loose, and by loose I mean it moved some when we changed a blade, which as we all know it's not suppose to do. And we tried to tighten it up by turning the bolts that align the part shown below at the red arrow, as these were the ones loose and causing it to be out of alignment and not correct.

(https://forestryforum.com/gallery/albums/userpics/10095/2617/scan0001.jpg)

We noticed that the part that the red arrow is pointing to was bent and that at least one of the adjustment bolts, where the blue arrow is pointing to, were stripped out of the block it is in. This is not good as this block is a welded part of the mill.

During a visit to the open house in Maine, he purchased a kit that had a new block in it and a piece that needed to be welded to the frame and then this block bolts to this new welded in mounting bracket block.
He had his friend at work, a mechanic, cut off the old block, and weld this new bracket-block to the frame, and paint it. It came out very nice.
He then installed the new roller block and slid in the new roller assembly that he got.
After all this was done, he called me and asked me to come over to his sawmill and help him align his blade.

I read all the instructions that came with the new piece he had welded in and this was done correctly. And the new instructions said to follow the standard alignment instructions that came with the manual.

Yesterday morning we aligned the blade per the regular instructions manual procedures, but we skipped some parts as the outer movable roller guide wasn't effected with this repair.

After creating the deflection, and aligning the roller as shown in the above drawing, and aligning the blade with the blade tilt tool:

(https://forestryforum.com/gallery/albums/userpics/10095/2617/scan0002.jpg)

we felt the new roller was in the correct position. And with all the adjustment jamb nuts tight we proceeded to saw some lumber.

Now we had the sawmill in a barn with the doors closed to hold what little heat we had, and we didn't want to run the sawmill engine a lot as it was a diesel, so we decided to grab an old beam he had on hand and try cutting it into 5/4 boards, which he needed for another window repair project.

Well it cut great boards each coming out 5/4" thick on each edge and we checked them in several places on each board. Both ends and several different spots in the middle.

However, I mentioned to him that these were boards that were created by using the 5/4 scale ruler and that the true test to alignment was creating and measuring the last board on the mill, between his clamp and the bed-rail dogs.

As we measured the last board it seemed that this one maybe off a bit. It was thicker by up to 1/16" or maybe a little more.

And I thought before we changed any other settings I'd ask you guys what would you do?

My first thought was to change the scale pointer to lower it by 1/16" but this could be the wrong solution as we set the blade height above the rail to 15" at the new roller and 15 1/16" at the other roller with the guide arm fully extended. And the pointer was pointing to exactly 15".

If the last board is truly too thick, what is the solution to make it the correct thickness?

He wanted to test the mill more by sawing out some logs and seeing if each one had a thick board left on the mill before we make any other setting changes. And I agreed with him that this one old beam was not be best piece to test the mill alignment on.

Any advice would be appreciated.

Thanks in advance.

Jim Rogers


Title: Re: Woodmizer LT40 blade alignment questions
Post by: logwalker on January 02, 2010, 05:00:27 PM
On my mill Jim, I just adjust the scale. It is movable on my 1994. Joe
Title: Re: Woodmizer LT40 blade alignment questions
Post by: ljmathias on January 02, 2010, 05:17:20 PM
Me too, Jim- mine was off a little before I checked it and I just adjusted it to be right- cuts great now and the last board comes out right no matter which thickness I'm cutting.

Lj
Title: Re: Woodmizer LT40 blade alignment questions
Post by: Jim_Rogers on January 02, 2010, 05:48:08 PM
Thanks for your advice.
I'll see what happens when he's sawn more logs, which may be a while.
But when I know what he/or I changed I'll post it.

Jim
Title: Re: Woodmizer LT40 blade alignment questions
Post by: Dave Shepard on January 02, 2010, 06:10:40 PM
If you've adjusted the guides to the bed per the book, then you adjust the scale to the height of the band. I think the book says to set the band at 12", and then move the pointer to 12". The pointer is attached to a piece of tin shielding to the right of the scaleboard. There are two 7/16" head bolts that you loosen.
Title: Re: Woodmizer LT40 blade alignment questions
Post by: Chuck White on January 02, 2010, 09:28:27 PM
Get your measurements from the blade to the bunk, then slide the scale to match!
Title: Re: Woodmizer LT40 blade alignment questions
Post by: MartyParsons on January 02, 2010, 10:52:30 PM
Measure to the bottom set tooth on the drive side. You can use 12" or 15" I usually do 18" the # is not important. Adjust the ruller ( scale )  to the same measurement as you get on the head to bed measurement on the drive side downward set tooth. Each bed rail should be the same. On the last board you sometimes get stress, sawdust under the cant etc. could be off 1/32.


Marty
Title: Re: Woodmizer LT40 blade alignment questions
Post by: Magicman on January 03, 2010, 09:16:53 AM
Quote from: MartyParsons on January 02, 2010, 10:52:30 PM
On the last board you sometimes get stress, sawdust under the cant etc. could be off 1/32. Marty 

That's why we call that bottom board the "dog board".  If anything goes wrong with sawing, or if anything is out of adjustment with the mill....it generally shows up on that bottom board.  I always try to point this out to customers.  If I see signs of stress, I'll stop and show them the cant lifting up on the end.  The customer needs to understand that the saw head doesn't raise up or lower during the cut.

I realize that this was "off subject", but blade alignment is just one of the variables that we deal with to provide quality lumber.
Title: Re: Woodmizer LT40 blade alignment questions
Post by: MartyParsons on January 03, 2010, 09:36:14 PM
Sounds like all you need to do is adjust the scale.
Title: Re: Woodmizer LT40 blade alignment questions
Post by: Jim_Rogers on January 04, 2010, 09:23:33 AM
Ok, thanks to all who have posted advice.

I'll pass it on to my friend next time I talk with him....