Buying tools in sets dramatically reduces the cost, and you’ll have a more complete selection when you need it.
Sawdust build-up can create heat and friction when you use a hole saw. One solution is to drill a smaller hole inside the area to be cut out that will allow the sawdust to escape. Size the relief hole according to the size of the larger hole. If, for example, you are cutting a 3-in. hole, drill a 1-in. relief hole. Don't drill the hole too close to the center, which you need for the saw's pilot bit.
Insects love warm electrical components and air conditioners are full of them. If you want to keep insects out, experts say do not use insecticides, because the electrical components will not like them. One option is to get a special cover for your relay switch, but be aware that it has to be installed by an air conditioning technician. The cheapest (and easiest) way to keep them away is to use a flea collar. To install the flea collar, shut the power off to the air conditioner and simply placed the collar near the relay switch.