uneven boards

[frodo]

i have a mighty mite band mill, i don't have any experience. it is set up to saw 24 feet , i was sawing a 16 foot oak, i had it down to a 6x6 all the time i was sawing one end would hold the thickness i wanted but when i got to the last three feet of the board the thickness would loose about half of an inch. this especially bummed me out when i sawed the first board off my 6x6 at an inch and a half, it was fine until the last three feet where it ended up being an inch. has anyone ever ran into this problem? oh yeah the mill is fully hydraulic

 

[Backwoods]

It sound like tension in the wood, as you are milling watch to see if the end lifts up off the bed of the mill. Sometimes turning the cant more often will minimize this but other times it will be one cut that releases the tension. If you are expecting it you can leave an extra ½ to the total thickness of the cant and then take a corrective cut when you see it move.

 

[redprospector]

If the blade is climbing, or diving in the cut there is something wrong in the set up of the mill, or quite possibly in the blade. If the blade is getting dull it will usually dive (at least on my mill). It could be set wrong for the wood you're cutting, or if the blade has been used much it could be no longer flat across the body of the band. I don't know what you've tried but if you haven't already, try putting a new blade on.
1/2" is a lot of stretch on the band, especially if it's rising in the cut.

Andy

 

[mountainlake]

Like backwoods said, tension in the log . The longer they are the worse it is, but varies a lot from log to log. Steve

 

[Kicker_92]

This would be one of the few areas that a CSM or ripsaw has an advantage. They cut at a constant depth referenced to the top of the log, rather than allways parallel to the bottom.

Also might want to check the mill setup, especially if there are any extension tables added to give you the 20ft length.

Can you post some pictures of your setup?

 

[frodo]

thanks guys the one end of the board was lifting up

 

[deeker]

If the blade is rising in the cut, checkout Cook's sawmill. They sell the super sharp blades, and "roll" the blade to make them flat. I have had blades rise in the cut that were set and sharp, still rose in the cut. Sent them back to Cook's and had them rolled. They came back and cut straight.

I have the Norwood LM2000, no hydraulics.....

Another thing that has been mentioned is tension in the log. Try cutting one board off, the flip the cant/log 90 degrees.

And the last one....check to make sure all of the bunks are parallel to the blade. And the log/cant is "dogged" down. Sometimes it can "lift" from the blades torque.

Kevin