Flatness?

[Satamax]

Hi everybody.

I was wondering how acurate were your mills over their lengh? I mean, would a 1/4" curve considered real bad over a 40' lengh? How's the blade wander too?

Thanks.

Max. 

[hackberry jake]

A slight curve isn't a problem since the lumber will staighten out in the stack. If it dries flat it will stay flat. The blade on my mill wonders about 1/16 at the most if it's being pushed a little too hard.

[T Welsh]

Satamax,I have a WM LT40HD,I think its a 1994 model year. It has seen over 1millionbf in its life time. I just finished cutting board and batten from a #1 butt poplar log 18 foot long and it is dead on the mark at 4/4 everywhere along the boards. remember though this is rough lumber that we are sawing and different people have different standards. I think a 1/32 + or - is acceptable 1/8 is pushing it. Tim

[Peter Drouin]

My Wm lt40super will cut flat. but when I cut 30' to 45' long I have to look out for stress in the log, If you don;t box the hart it will lift off the deck then one side wont be flat :D :D but you have start out with a straight log too :D :D .it;s all fun 8) 8) 8)

[piller]

Suppose you are cutting a 16 or 20 foot long 8 x 8 timber, you make one cut then rotate the log 180 degrees and set the saw for an 8" cut and make the cut.  Any errors will now add instead of cancel, can you still get 1/16" accuracy over the entire length of the timber?

[Satamax]

Thanks a lot guys.

I was just wondering what was common practice in the sawmill community.

So if i understood well,

1/32 per face is good, 1/16 per face is average, and 1/8 people will start to frown at me  ;D

Thanks again.

[Brucer]

Level all the supports on your mill according to the manual. Then the only variation you get will be caused by sawing out stresses in the log.

For 1" side lumber I might see up to 1/16" variation between the ends end the center. It's not a big deal for stock lumber -- the trim saw takes care of it. For FOHC timbers I will sometimes saw 1/2" oversize and then do an extra cut on each face to make it absolutely uniform.

[ladylake]

Yes as Bruce said the only way to deal with stress on long timbers is to cut over sized and make sure the cant is laying on all the bunks on the last cut.   Steve

[Satamax]

Bruce, i don't have a mill, i'm planing to make one. Well, i have the wheels and frame. :D

[Brucer]

So make sure the frame doesn't have any vertical waves in it (at least the tracks) and make sure you have a method of leveling the log supports independently ;D.