Bandmill Blade Tension

Quick tips on blade choice and blade tension. August 18, 2009

I own a Wood-Mizer LT40 sawmill. What type of blade works best for pine, and what tension should the blade be set to for best cuts? On average, how often should the blades be changed, and what is the best indication?

Forum Responses
(Sawing and Drying Forum)
From contributor D:
For run of the mill pine logs - 45 or 55, 10 degree bands work fine. For knotty pine, I now use nothing but WM 1 1/8" tooth spacing 55 10 degree bands. Even the 4 degree didn't help me with knotty pine - the 1 1/8" spacing bands did the trick, even in very wide cuts. For all sawing, run the tension up to the upper end of the orange on the pressure gauge. Keep an eye on it, and readjust as necessary.

Got a debarker? If so, change after about 750 board feet.

What to watch for depends to some degree on your mill's power plant. If you have one of the big diesel mill 53 CAT, 42 Kubota, you won't notice the mill react to a dulling band, you have to watch the cut. If it cuts smooth and straight (especially at knots and hard spots, and especially in wide cuts), then it's still sharp enough to do the job. But even with good results, don't push the band too far - the micro cracks in the gullet will cause even a perfectly sharp blade to bust if pushed past its limits.

From contributor A:
I saw around 900 tons a year of SYP and it is cut with WM 10 degree 0.045 blades. We have cut some with the new 1 1/8 spaced blades on the LT70 with 10 degree 0.055. Most of the time we average over 1 mbdft per blade change. I have sawn over 2 mbdft before the blade will break. The 13 degree blades really fly through pretty clear logs but jump really bad knots. The 10 degrees do better overall, but you still need to slow down on large knots. On the LT40HDG25, I run 2,200 on the gauge.

From contributor R:

What do you use as a lubricant when cutting SYP? I have seen guys use Pine-sol or diesel. Which one works best to keep the blade free of pitch?

From contributor W:
Wood-Mizer recommends that you change the .055 thick blades every two hours of sawing. The issue isn't getting the blade dull, but the micro-cracks contributor A was talking about, which are caused by the band revolving around the wheels.

If you can find it, Cotton Gin spindle cleaner works pretty well. I mix about 8 ounces/5 gallons of water when cutting resinous woods...