Aluminium Drill entry material to prevent drill breakage by centering the drill bit. In addition, the entry material helps avoid copper burrs, reduce contamination in the hole and on the drill bit, and prevent pressure foot marks from the drilling machine. Although aluminum composites are typically the most expensive, they do a tremendous job improving accuracy and dissipating heat. In addition, they leave no hole contamination. Solid aluminum provides good burr suppression and no contamination, with only a slight increase in the risk of drill bit breakage for very small diameter drill bits. Supplied as 300m x 300mm x 0.2mm Thick Sheets other sizes available by request