Recently I had an unusual blade vibration problem with my bandsaw related to a bad tire That made me realize that there are three different types of vibration issues.
In my experience, blade flutter is usually related to blade tension. With the bandsaw running, look straight into the blade. If you see the blade travelling straight done in a line, then there is no flutter. However, sometimes the blade will oscillate from side to side, which makes the blade look wider than it really is. This problem will cause “ripples” to in your saw cut rather than the usual consistent vertical lines. I have always been able to get this to go away be increasing or decreasing the tension some. Certain tensions setup a harmonic vibration and changing the tension makes it go away. Try more tension first.
At least once I received a blade with a bad weld. The back edge of the blade was not lined up properly, which created an uneven blade back. This caused a “ticking” sound as the blade hit the thrust bearing periodically.
To diagnose this problem, turn the wheel by hand and watch the back of the blade in relation to the thrust bearing. You should see it getting closer and and further from the bearing as you turn the wheel. If it gets closer at the same place on the blade each time, then it’s the blade. If it gets closer at a different place each time, then it’s the wheel…
I replaced the bottom tire on my bandsaw with a Carter Urethane Band Saw Tire. The tire was pretty easy to put on, but the tire is only 7/8" wide and the wheel on the Jet saw is 1" wide. I got the tire centered the best I could on the wheel, but figured it would be fine. Wrong!
The tire slides back and forth across the width of the wheel. I’m not exactly sure when this happens, but I suspect it moves the most when applying and releasing tension. As the tire carries the blade around, the misaligned tire causes the blade to oscillate back and forth. In my case, I looked at the side of the blade while the saw was running and noticed significant oscillation. Since I was using a relatively new blade, I immediately suspected the blade, so I did the test above for the bad weld. As I turned the blade by hand, I noticed that the blade got closer to the thrust bearing at a different point on the blade with each revolution. Initially this puzzled me, but then I realized that the blade got closer to the bearing when the wheels were in the same position each time. The tire was pulling the blade back and forth.
If a urethane tire is not on the wheel straight, it will carry the blade back and forth, causing oscillation that is visible from the side of the blade.