by Lowell Freeborn
The information for this article was taken from Lowell Freeborn's "Carbide Saw Manuel." There are many more great articles based on the information in his book in our Saw Blade Index.
This is a very elusive subject and the cure has baffled many people for a long, long time.
The first thing that should be recognized is where the sound comes from. There are three main sources of sound. Number 1 is Air Noise created by the fan action of the teeth. Number 2 is Plate Noise created by plate vibration induced into the body of the plate by both the air turbulence and the material being cut. Number 3 is Cutting Noise.
Air noise can be down to a soft purr or up to a high ear piercing siren type sound. The air noise generally is progressive with the rim speed of the saw. At low R.P.M. the saw noise may be bearable, but as the R.P.M. is increased so is the noise. If saws could all be run at a fixed rim speed, it would be a lot easier to design teeth in such a way that you could predict the air noise level. Of course, saws run at all different rim speeds so we have to compromise and attempt to design saw tooth geometry so the saw will do a satisfactory job and disturb the air as little as possible.
Saw Plate noise is started by the action of the teeth fan in the air and creating a vibration in the saw plate. Each saw plate seems to have its own sound. The plates that vibrate at an annoying frequency are the trouble makers. Saw plates that are manufactured to the very same specifications will not necessarily produce the same sound. Plate noise can be altered by numerous methods. The most common is to install expansion slots in the rim of the saw. The next effort would be to plug the expansion slot holes with a soft metal or plastic plug. Going further with plate sound, it is possible to cement sound deadening material to the sides of the plate. Plates are also laminated with different metals. These approaches only tend to make hammering and servicing more difficult. See our article on Hammering Saw Blades.
Cutting noise is a tough problem and it occurs from the teeth producing chips and then throwing them at a high velocity, thus creating a noise by the chips accelerating through the air and also contacting each other. The problem here is the size of the chips. Large chips have greater velocity than small ones and make more noise on impact with other chips or other objects. In considering cutting noise it is necessary to reduce the chip size and shape. This can be done in many ways. One way is to put more teeth in the saw. Decreasing the feed speed will also reduce chip size. Altering tooth geometry can be effective. In any event a change in chip shape and size must be accomplished. See our articles on Saw Tooth Quantitiy, and Feed Speed, and our Saw Blade Design article for more information.
In summarizing saw noise, it should be noted that a lot of things can be done to generally improve noise. There are, however, a lot of noise problems that must be dealt with individually and in some cases the actual noise must be stopped by deadening the object being cut. We also must recognize that there are so many different operating conditions and materials to saw that it is impossible to curb saw noise by approaching the problem from just one aspect. About the time you feel you have solved the problem, you'll find that another one exists. Time, study, and patience are what it is going to take.