Troubleshooting a Wandering Bandsaw Blade

Bandsaw blades may wander for many different reasons. October 1, 2010

Question
We have a portable bandsaw mill with a 2 blade on 30 wheels. When you cut 5/4 inch hardwood boards, what would cause the blade to wander from 3/8 to 3/4 inch up and down? Could the blade be loosening up? The blade is new, and it appears to be tight by hand, but it may not be tight enough?

Forum Responses
(Sawing and Drying Forum)
From contributor N:
Tension could be the problem. I am by no means an expert on the subject, but I used to have that problem with my mill and 1.25'' blades until I talked with Cook's Saw and Machine. I ended up buying their blade roller, and it is worth every penny once you know how to work it.



From Professor Gene Wengert, forum technical advisor:
The blade can wander because it is not being held tight enough. The blade must be under tension. One of the 30" wheels should be adjustable to create the needed tension. Otherwise, the blade will want to follow the grain and/or leave the cut. The blade can wander because the teeth are sharpened at an incorrect angle. The blade can wander because the tooth design is not appropriate for higher density species (and vice versa). The blade can wander because the feed is too slow or too fast for the blade. The blade can wander because the bearings are bad or the wheels are misaligned. The blade can wander because the blade is heating; the heat can come from inadequate set, pitch buildup, poorly set guides and a few other less common reasons including a heated bearing. I am always surprised how often a fresh blade out of the box is poorly sharpened.


From contributor P:
When my band starts wandering (before I assume the blade is dull), I detension the blade, clean out the guides (or check for proper guide operation and alignment), retension and try again. If it still is wavy, I crank up the tension and try again. If it is still wavy, I replace the blade and that cures it.

You can also look for flutter in the blade while it's running by looking at the top portion of the band. This is often a sign of too little (or too much) tension.