How To Calculate The Bandsaw Blade Speed
The speed rate is the difference in speeds that a bandsaw has when cutting differing materials. SFPM, which is referenced multiple times in bandsaw reviews, is the speed rate, also known as Surface Feet Per Minute. The speed rate can be controlled by multiple different ways. Variable pulley, fixed pulley, and electronic drive are three of the main ways that speed rate can be controlled. Determining the correct speed rate for the material you are cutting is necessary for controlling the lifespan of your bandsaw blade. Once you have speed rate down, you will not have to buy bandsaw blades as often.
The main rule that you should use when calculating speed rate is called the “100-200-300 Rule”. This rule of thumb will make it easier to optimize your blade speed.
What does the 100-200-300 Rule actually mean?
- When cutting hard materials, a starting speed rate of 100SFPM will run at 98.42ft/min.
- When cutting medium materials, a starting speed rate of 200SFPM will run at 196.85ft/min.
- When cutting soft materials, a starting speed rate of 300SFPM will run at 328.08ft/min.
Keep in mind the speeds listed above are an average of various manufacturers. This rule was put into place to give a general overview of appropriate blade speeds when cutting various materials.
Most bandsaws on the market have variable speed settings. This allows you to chose the right speed for the right material. For bandsaws that do not have a variable speed setting, it is often common practice to run a saw at around 300SFPM unless cutting non-ferrous metals such as brass, copper, aluminum or thin steel.
There are a couple ways in order to know whether or not you have your toolset to the right speed. The color of chips and the shape of the chips are the most common ways to check this. These ways will also make it known if you have a feel for the correct feed rate. You want to get tightly curled and thin chips out of the tool. If you see the chips getting darker in color this means you are burning the material or force-feeding the material through the tool to quickly. The worst color chips that you can see are blue. If your chips come out the blue in color, you need to take extreme caution not to damage your blade or even your tool.
Speed rate is restricted by the density of the material and the heat produced during the cutting process. The faster the blade is spinning, then the more heat and friction will be produced. This causes blades to not last as long.
Blade speed needs to match the type of material you are trying to cut. If the blade speed is too high, the blade may be dull and need to be replaced. If may make tougher jobs far more difficult. Too slow of blade speed can cause issues as well, including inefficient production and not being able to cut through a material causing teeth to wear quickly.
As general practice when determining blade speed when cutting differing materials, if the material is very hard you need to let the tool take its time and work its way through the material on a slow speed. If the material is light such as non-ferrous metals, you can kick the speed up a bit and get the job done faster. Faster speeds will give a smoother finish on the surface.