This is not a band you want holding up your hair. Bandsaws are an essential tool to a woodworker, with uses in furniture making and traditional boat building. As always, we will go into some of the history of this tool, some attributes of wood as a material, and my experiences with this tool.

 

The fundamentals of a bandsaw have been unchanged since the first patent appeared in 1809, but the first working design was made in the 1830s. Believe it or not the tool started large rather than small, with a blade 34-feet long, 9 inches wide, and the thickness of a magazine. The main benefit of a bandsaw blade was also the reason there was a technological problem at hand: the blade is extremely flexible. An example of one of these old patents is shown below.

The saw consists of two large wheels, with one attached to a motor with a band called a rubber tire. Around this wheel is the bandsaw blade: a large hoop of metal with cutting teeth on one side. There are bearings on either side of the blade as the wheels rotate to keep the blade straight, and there is a specific tension needed so it does not snap under the pressure within the wood.

Wood is a unique material to work with because it has many years of internal tension. The former tree trunk has many locations of internal tension from holding up the heavy branches of the tree. Although the branches are cut off in the processing stage, that internal stress remains, and when cutting the fibers of the wood in certain directions, the wood can press into the side of the blade.

There are two wood directions that must be considered when using traditional cutting methods. There is with the grain, which is along the long streaks you see in a piece of wood. Cutting in this direction is called ripping the wood, since you rip the wood fibers in the direction they run. If you cut perpendicular, you are cutting cross grain. This requires much more force since the grain direction resists the cut. Think about chopping firewood; you never cut the trunk from the side, you cut it from the circular top!

Bandsaws are extremely versatile because they can make curved cuts in the wood, moving from ripping to cross cuts, and anything in between. Band saws can easily be used with a jig to cut out circles, or curved edges in a flat slab of wood. Since the blade is massive on these tools, the gate can be lifted to perform a process called resawing, where a thick slab is cut in two thinner ones. This is impossible without a looped blade. The flexible blade allows you to cut a changing bevel, where the angle of the cut changes as you move down the length. This is used extensively in boatbuilding for the frames or ribs of a boat, which must have exact angles to meet the inner side of the planks.

*Picture from the Tally Ho rebuild project on YouTube; an example of a changing bevel in  boatbuilding.

I own a hobby bandsaw and have used it a few times for cutting small pieces of wood for rings or display knives. I also used these tools in my woodworking internship to make many push blocks. These are handled pieces of sacrificial plywood that have a butt on the end to push wood into a table saw, keeping a tight grip while positioning your hands away from the dangerous blade. The design that the shop used was a curved and ergonomic one, so the bandsaw was perfect for cutting out sharp curves.

I also made use of relief cuts, where I approached the line I was cutting perpendicularly at many points. Therefore along the way, if the curve was too severe or if there was too much tension, I had a checkpoint where I could meet the relief cut and I could reposition the piece.

Overall, it’s a wacky looking tool but it has an essential purpose in fine woodworking.

 

Sources:

Pre History Of Band Saws – VintageMachinery.org Knowledge Base (Wiki)