One problem with owning a small or bench top bandsaw is that blade manufacturers expect you will only use it like an over-grown scroll saw. You saw may have the capacity to cut 4, 5, or even 6-inches of thickness, but the commonly available blades almost always have a tooth count between 6 and 10 TPI (teeth per inch). This is great for producing smooth cuts in thin material. However, if you attempt to cut through a two-inch (or greater) piece of wood, you will find the blade wanders, burns the wood, and seems extremely slow.
The reason for this poor performance is that there are TOO MANY TEETH on the blade! That’s right, too many.
As the blade passes through the stock, each tooth scoops out material until the gullet ( the empty space ahead of the tooth) fills up. If the gullet is filled before the tooth exits the bottom of the cut, the packed-in waste material pushes the tooth away from the face of the cut. This forces you to push the work piece harder, creating friction and burning, and forcing the blade to wander in the cut.
On the other hand, if the tooth passes through the work before the gullet is full, the tooth rides cleanly and smoothly against the face of the cut. This means you don’t need to force the work piece to move, there is minimal friction, and the blade is much less prone to wander.
I came upon the idea of removing teeth from my blade after reading an article on sharpening bandsaw blades by Matthias Wandel. Be sure to check out the cool stuff Matthias does at his website, Woodgears.ca.
The technique is simple, and can be done with the blade still on the saw. Grab a Dremel-type rotary tool with a cutoff wheel attached, and follow these steps:
- Unplug the bandsaw. Otherwise it may totally ruin your day.
- Open one of the wheel covers and rotate the blade so the first tooth to remove is near the table.
- Hold the rotary tool at an angle similar to holding a pencil to write, and grind away the first tooth. It isn’t necessary to finesse the shape of the resulting blank space, but try to avoid cutting deeper than the original gullets.
- Rotate the blade down by 2 teeth, and repeat the grinding.
Removing every other tooth should provide plenty of gullet space to handle material as thick as the capacity of the saw. My example is a saw with 10-inch wheels, and the blade is 70.5 inches long. Grinding away the extra teeth took about 15 minutes. Note that I was not attempting to sharpen the remaining teeth.
You might also notice that bandsaw teeth have a ‘set’, just like hand saws. The teeth are bent slightly to alternate sides of the blade to clear space for the body of the blade to move. More set allows tighter turning radii, as there is more space in the cut to make a turn.
It may seem that removing every other tooth would ruin the blade, leaving all the remaining teeth set in the same direction. Yes, this would be a bad thing, but fortunately, the teeth on my blades are set in a 3-tooth pattern. They go left, right, straight – left, right, straight. Removing every other tooth leaves the set pattern close enough to original that it doesn’t matter.
Before performing this operation on my blade, I found it nearly impossible to cut through a 2-inch thick piece of hard wood. The cut would start cleanly enough, but only a short distance in, and it became noticeably more difficult to push the work piece. The blade became impossible to keep straight, and closer examination revealed a good deal of burning. After removing the extra teeth, the saw cut through two inch thick white oak like the proverbial hot knife through butter!
I admit, some people may consider a modification like this to be dangerous. I suppose it is possible to cut too far into the blade, and cause it to break during use. I accept no responsibility for accidents resulting from this technique, so try it at your own risk.
To help illustrate this technique, I have included a short video. Please enjoy the music, and feel free to comment, as feedback is always welcome.
Until next time,
Savor the Sawdust!