Behind aluminum siding are voids where the siding does not contact the house's sheathing. When drilling a hole in the siding, you must take care not to dent the siding in the area of the hole. Minimizing the amount of pressure that you exert on the drill bit will prevent the siding from denting and reduce the chances of the drill bit catching on the thin aluminum that comprises the siding. If you are drilling a large-diameter hole with a hole saw, take care to avoid the hole saw from catching and causing irreparable damage to the siding.
Insert the drill bit or hole saw into the chuck of the drill motor.
Place the tip of the drill bit on the center location of the finished hole.
Apply light pressure to the back of the drill motor. If you notice the aluminum siding buckling, reduce the pressure on the drill slightly, as this could dent the siding.
Wearing your safety glasses, begin drilling the hole. When using a hole saw to drill the hole in aluminum siding, keep the saw slightly tilted to one side to reduce the chances that the hole saw will bind while cutting the hole. If you notice that the saw binds, pull the hole saw away from the siding, tilt the hole saw in a different direction and restart drilling the hole. A binding hole saw can tear and deform thin aluminum siding.
Reduce the pressure you have applied to the drill motor when you feel the metal "give." This signifies that you are almost through the aluminum siding.
Stop applying pressure when you drill through the aluminum siding, but keep the drill bit turning.
Slowly pull the revolving drill bit from the hole.
Clean the bur from around larger holes with a half-round bastard file.