Drilling aluminium plate material can be difficult due to the softness of aluminium. Proper equipment and patience are critical to achieving a nice clean drill hole in aluminium. Due to the soft nature of aluminium it is easy to push any type of drill bit through an aluminium plate. However, in most cases that approach will result in ruined drill bits and rough edges around the drilled hole.
Place the aluminium plate on the wooden block and use the clamps to secure the aluminium plate in place.
Attach a piece of packing tape over the area where the hole will be drilled. Mark the location of the hole on the tape.
Put on eye protection. Select a drill bit that is several sizes smaller than the desired hole diameter to drill the pilot hole. It is best to drill aluminium on slower settings to avoid heating the aluminium and having it adhere to the drill bit. Align the drill bit on the marked hole location and begin drilling. Do not exert excessive pressure on the drill bit as this can create too much heat and melt the aluminium. Add 3 in 1 oil to the drill hole for lubrication.
For best results, select a second slightly larger drill bit and repeat the above process for the second pass through the hole. This second bit should be slightly smaller than the desired hole diameter.
Select the drill bit for the desired hole diameter and repeat the steps in the drilling process. After the hole has been drilled remove the packing tape from the surface of the aluminium plate. If there are burrs on the edge of the drill hole, select the appropriately sized countersink bit and countersink the drill hole to remove the burrs. Make sure to not drill the countersink more than slightly beyond the surface of the aluminium, especially for thinner aluminium plating.
It is very important to secure the aluminium plate to the wooden block. An unsecured piece of aluminium can become stuck to a drill bit and beginning rapidly spinning. The sharp edges of a spinning aluminium plate are quite dangerous.