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Started by dooghi, November 25, 2005, 10:09:18 AM

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dooghi

I just found this forum, looks great. I am in eastern Colorado not many trees but I cut old powerline poles. My mill is a homade one fashioned after a WoodMizer. Had it about three years and am leaning as I go. I do have two persistent problems that I have yet to figure out. They are why,  does my cants which by the way are 18 to 20 feet long always end up thinner in the middle then on each end, and why does my blade crown up as I cut, not always but pretty often? Any help would be great as there is no one out here that mills. Thanks Doug

Kirk_Allen

Welcome to Forestry Forum! 

The problem you described could be several things.
First problem of thin in the middle cants.

1.Homeade mill?  Possible dib in the middle of the rails of the mill
2. I would suspect it is from stress in the poles.  I cut a fair number of them and have seen this problem. 

Turning the pole more often helps but depending on the size from end to end you may have to cut the stress out with a trimm cut or two.  Smaller diameter poles will have this problem more than larger ones.

Crowning up while cutting
1. Dull blades is the most common crowning problem I have seen.  If the problem goes away with blade changes then that should point you in the right direction.  Depending on what kind of poles your cutting, they are TOUGH on blades.  Especialy Western Red Cedar. 
2. Blade Guides out of adjustment. 
3. Not enough downward blade deflection
4. Improper Tension

These are the things that come to mind but I am sure some of our resident experts will jump in and cover a boat load of things I missed.  You came to the right site to find the answers and again, welcome to the best site on the internet.




IL Bull

Check your plow angle of the blade.  It should be horizontal with a straight edge placed on the bunks.
Case Skid Steer,  Ford Backhoe,  Allis WD45 and Burg Manual Sawmill

D._Frederick

doo.,

Since your mill is home made, is your tracks perfect level and straight? If not, your cants will be shaped like your track.

How are you measuring blade tension? If you are using carbon blades, a 1 1/4 X 0.042 blade should have a force on the band wheels of about 2200-2400lbs.

Your backup roller on your guides should be within 0.025 inchs of touching the back of the blade when the band wheel are turned by hand and the band is at operating tension.

Who is setting the set of your saw teeth? The set should be about 0.022 to 0.025 inches per tooth for the wood you are cutting.

rbarshaw

Pictures, got to have pictures.

As to the blade rising, The two main problems I had are;
1. Dull blade.
2. Some interference with the teeth, Ie; there is something hitting the teeth from the side like the guide causing them to to be straightened on one side, or a wheel.

The cant's being thinner in the middle, take a nilon string and streach it from one end of the rail the mill rolls on to the other with a equal spacer at each end holding the string off the rail slightly, then measure the distance between the rail and string at several points. Do this on both sides, if the measurements are not all equal, that's your problem. I expect you'll find it is lower, ie; a bigger gap, in the middle. The log bunks can be checked the same way.
Been doing so much with so little for so long I can now do anything with nothing, except help from y'all!
By the way rbarshaw is short for Robert Barshaw.
My Second Mill Is Shopbuilt 64HP,37" wheels, still a work in progress.

dooghi

Will try to get pics asap. Seems that like putting a blade on inside out some things just don't sink in. After readingposts and other stuff on this site went out and lowered jacks on both ends pulled a string and cutt some cants and they were within a 1/16 end to end. Some times you can't see the forest for the trees :D I have rollers for blade guides and lost a bearing on one of them had to finish cutting without it seemed to cut better, I will do some looking to redo blade guides so they are adjustable. Change is good  smiley_annoyed01

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