Bandmill wheels and blade speed
Do larger bandsaw wheels mean increased sawing speed? January 31, 2001
What is the difference in sawing speeds between different sizes of bandwheels? Would I get more speed from a 24" than an 18"?
Any increase in drive wheel diameter will cause an increase in speed if the motor is capable of maintaining the same RPM. Since a larger circumference will go around the same number of times at the same RPM, the linear speed of a point on the wheel, or blade speed, will be faster. I think in your scenario it would be close to 1/3 faster.
I understand that you can make the blade go faster with larger wheels. But why? Don't blades have a certain optimum speed? Would faster speeds overheat the blade?
Faster blade speeds means each tooth does less work. Therefore, the blade lasts longer. There are many variables in cutting speed, including how sharp the blade is.
Faster blade speed also means faster feed rate. You don't want each tooth to do less, but rather each tooth to do the exact same amount of work.
If you increase the speed of the blade, without increasing the feed rate, the teeth will take a smaller bite. A smaller bite means finer sawdust. Fine sawdust will spill past the gullets and heat up the blade--circular and band. Heat causes many problems, resulting in poorly cut lumber and shorter blade life.
Wheel diameter is directly proportional to the thickness of the blade. Bigger wheels enable the use of thicker blade stock tooth spacing is directly proportional to the appropriate blade speed. Thicker (larger) blades have more beam strength. Therefore bigger band wheels enable the use of thicker, stronger blades, operated at greater FPM and result in better, faster cutting.