Dave Baseley wrote "I had heard that the holes ( in SR brake levers ) were pierced rather than drilled which I took to mean that the holes were done while the material was at an elevated temperature" While I can't comment on the metallurgical consequences of doing it this way in my mind it is more than likely that your informant meant that the holes were punched.In my experience with the making of press tools, the undeveloped shape of the brake lever along with any holes that the finished part will contain would be punched out.Sometimes this is done in a number of different operations or stages in the same tool.The resultant flat piece of aluminium is then formed into the required shape.Sometimes, but not always in yet another tool.Depending on the depth of forming required then this may also take place over a couple of stages in order not to stretch the material too far in one go and crack it.Hope this helps Geoff Duke in Wintery wet Melbourne Australia