Greetings from rk Miles tool department! Summer is over and the hard work you have completed around the house and on the jobsite has done a number on your power tools! All of those beloved power tools you have been using have wear parts that need service. Through this 3 part series we can get that tool back in the field with some simple tools and little bit of know-how from rk Miles. In our last installment we discussed carbon brushes and their role in the power tool. Now, onto switches.Today we will be discussing the switch or VSR (Variable Speed Switch) and its role in the power tool. There are two types of switches: Regular on/off switches as found in circular saws, routers etc., and VSR switches, found in any variable speed tool such as a cordless drill. Standard on/off switches, sometimes called toggle switches, are usually the type of switch that will go bad with little to no warning. One minute the tool works fine, the next time the switch is pulled nothing happens… Very frustrating. There are no serviceable parts in toggle switches, which means the unit needs to be pulled and replaced.

VSR switches will start to show signs of wear. Unlike the toggle style switch, VSR switches can be defective and still work. A defective VSR switch may last years for turning on and off the tool at full speed but can lose all its ability to regulate the speed of the device. The switch will develop “dead spots,” making the tool turn on erratically or not at all. The “dead spots” that develop in the switch will make certain speeds of the tool not work at all. Eventually the switch will make operation of the tool impossible. Again at this point the entire switch needs to be replaced.

When replacing a switch make sure the battery or cord is disconnected. All of the screws that hold the tool together will need to come out. Once inside make sure to make note of where all the wires go. With today’s modern cell phones, taking a picture with your camera-phone is a great way to document how the wires should go. Usually a switch is held in with two screws, however more may be present. When replacing a switch only use hand tools for tightening screws because getting the screws re-tightened to just snug is all you will need.

While your tool is opened up- this is a good time to clean the inside of it. Dust dirt and debris can work its way into the tool. Too much dust and dirt can cause the tool to overheat and, as we discussed in the last article, too much heat causes most tools to fail. Clean the dust out with a little compressed air. Do not use any cleaners or chemicals as there are exposed electrical connections present.

Once your switch is installed and the case put back together, test your tool. If it does not work, the next step is to check all of your electrical connections. Going online and typing the model number of your tool into a search engine should give you a schematic of the tool like the one shown here. If you get stuck with your tool and nothing seems to help… stop by rk Miles and we will be glad to help you!!

Remember, trained professionals are the ultimate caretakers of your equipment and this guide is to be used to get you out of a jam and just give you a little information as to how your tools work. As a general rule always remember…. Work smart and make safety a priority! Have fun out there!

Jon Glinski
rk Miles- Middlebury



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