Bandsaw Modification
Project Background
Band saws, both vertical and horizontal, are extremely useful for a wide variety of cutting applications. I usually do my material-cutting by hand, whether it be wood cutting with a wood saw or metal with a hack-saw. When I started designing my lathe, learning about precision tooling and the rigidity necessary in precise machines like professional metal lathes, I realized that I couldn’t work with the wood framing that I had originally planned to use as the base structure of the lathe. I then thought I would cast the base from aluminum, but quickly changed my mind and opted for a steel base on which to mount the components.
The amount of metal cutting involved in shaping the sections of the lathe’s base would be next to impossible to perform by hand, so I went to my University’s machine shop to see if they’d allow me to use their band saw for my metal cutting if I replaced the blades after heavy usage of their current saw blades. I was told that I could pay them instead to waterjet-cut my parts to shape but that I couldn’t use their band saw for such a large amount of cutting, however just for two simple cutting operations I would have been charged 325 dollars. As a graduating student I didn’t have the kind of money necessary to fund such an operation and decided instead to search for a cheap band saw online.
I settled on a WEN 10-inch band saw which I acquired for only $250, the cheapest that I could find for a saw of its power-capability and size. I quickly learned that the cutting speeds and force offered by this saw were far from acceptable for steel cutting. The lower of the two speeds available on the saw is 1520 surface-feet-per-minute of blade travel, which is generally a good speed for cutting aluminum, most types of wood, and plastics. Harder metals, however, like steel and brass, require lower cutting speeds and higher cutting forces, to limit heat-buildup due to friction and prevent the motor from stalling due to those cutting forces.
Once I got my band saw, I tested it on wood and calibrated the guides and table, then began modeling the saw in Creo and determining how I could adjust the ratio between the motor and blade. I ended up with a version of the saw that would allow me to toggle through speeds of 2620, 1520, 900, 750, 520, 430, 250 and 150 surface feet per minute. These new speeds would allow me to cover a large range of materials including the mild steel that I planned to cut, which generally performs best at cutting speeds between 150 and 300 sfpm.
I used my welder to create some framing for the pillow block bearings that I would need to mount the new axles and their pulleys to and drilled the necessary holes in the frames, making sure not to structurally compromise them in any way. All that remained was to purchase the pulleys, belts, bearings, fasteners and shafts, and assemble it. I took a break from mounting everything in order to work on this site, so it is not yet in working condition. Once everything is mounted solidly with the necessary tolerances it should allow me to cut steel with the metal-cutting blade that I purchased.
