When wishing to drill somewhere near square to a surface a simple guide block can pay dividends. The scrap of steel shown in the photo was an offcut from a local machine shop through which I drilled 3.2mm, 4.8mm and 6.4mm diameter holes. These sizes are good for giving a small tolerance to 1/8", 3/16" and 1/4" drills. The bracket is positioned, all holes are started by about 2mm, when the bracket is removed the drill bit is passed through the guide block and the tip of the bit is carefully located in the started hole.The guide is then held down firmly whilst drilling. The clamp is holding a block of wood under the hole position to prevent burst through. This method can be surprisingly accurate. Duds |