16 - Custonize Your Radial Arm Saw, страница 25
THE SHOP Tool Selection . If you're planning to buy a new tool, one of the simplest things you can do is select a quiet one. While some manufacturers include decibel readings along with other information about the tool, that seems to be the exception — not the rule. noise test. So what i do is fire up the tool in the store. After all, if it's too loud in a wide open space, it's not going to get any quieter when you bring it into a small shop. features. Another thing that's worth considering before buying a tool is the features it has that can contribute to quieter operation. This is especially true of the motor, drive system, and the speed of operation. MOTOR One thing that affects the noise produced by a tool is the type of motor. Because it runs at a higher speed, a universal (brush-type) motor is louder than an induction (brushless) motor. Note: To tell them apart, check for the "caps" that hold the brushes in place. Although most hand-held power tools use a universal motor, you'll often have a choice when buying a stationary power tool, see photos. DRIVE SVSTEM The drive system of a tool also makes a difference in the noise it generates. As a rule of thumb, a gear-driven tool inns louder than one that's belt-driven, see photos. The reason is simple. There's a certain amount of "transmission" noise caused by the gears meshing together. But if you transfer powrer from the motor to the blade through a belt, it eliminates this noise. VARIABLE SPEED Although it's not specifically designed to reduce noise, a tool with a variable speed control can be set to run considerably slower and quieter than a single speed tool. For example, the decibel reading of the variable speed router in the left photo drops from 100 dB to 78 dB at the slowest speed. If you already have a fixed speed router, you can use a control like the one in the photo at right. A Universal Motor. Because it operates at high speed, a tool with a universal motor runs louder. A Gear-Driven. A tool that transfers power through a system of gears tends to run louder. A Variable Speed. A router with a built-in variable speed control can be set to run slower and quieter. A Speed Control. To reduce the RPM's (and noise) of a fixed speed router, use a speed control unit. A Belt-Driven. A belt-driven tool offers a quieter method of getting power from the motor to the blade. A Induction Motor. A heavy motor housing and slower speed contribute to a quieter running tool. No. 16 ShopNotes 25 |
