By far the most common complaint we hear from new customers and novice band saw operators is that they´re breaking blades way too soon. It´s hard to explain verbally so I made these drawings with red arrows and bold text to graphically describe the overwhelming stress that blades are subjected to every day by uncaring operators. Conventional wisdom would have us believe that 3-wheeled band saws inherently break blades because they have to go around too many small wheels, instead of two big wheels. To some extent that might be true, but the degree of stress a blade experiences going around a 5" radius isn´t nearly as severe as what it goes through when bent around a 1/2" radius bend. It doesn´t have to stay at that angle very long to have been "bent". Once you bend it, its bent. If you take two pair of pliers and "work" a blade weld from 5" on either side it´ll take a long time and a lot of bending before the weld will fail; but move those pliers in close and you can break a weld in seconds. So it is when the blade spins around the saw at 76´/sec. That´s 1410 blade revolutions per minute. It´ll take a long time to over-"work" a blade around 5" radii; but not long at all to break it when the bend radius is 1" or less. We constantly advise our customers to keep the blade running straight from top to bottom but never actually calculated the math before. The diagrams below should speak for themselves. The consequences in breakage of running a saw off-center to the blade, or "shifted", are the most severe and the easiest to fix. Just slide the saw sideways over to the kerf when you first notice the blade "leaning" against a guide roller. As a rule, I set the pinch rollers wide enough to see air between them and the blade. If the blade makes contact with a roller I immediately correct by shifting back to center. Another common cause of weld failure is almost impossible to see from the operator´s viewpoint and involves your choice of blades. If the blade gets deflected by internal knots or drifts away from a cross grain (insufficient set angle) it will come out the bottom off-center to the wheels and bend (1/4"?) immediately to fit back into the lower blade guide rollers. Then it wraps around that 1/2" radius roller (even worse if you´re using blocks) to return to the lower wheel. Talk about "working" a weld! The only cure for this is to change blades for a wider set and try again. The math is extremely rounded but interesting. Correct me if I´m wrong.