I trued the block square and straight and then ripped it down the length so that one half measured approximately 5/16″ (8mm) and the other 3/8″ (10mm). You could also start with two separate pieces of wood, as long as they are square and the same height.

Even with experience, it can be difficult to drill holes square to the wood in both directions with a handheld drill no matter the type. Portable and pocket-sized, this guide block will ensure perpendicular drilling alignment wherever you go. The Milescraft DrillBlock allows you to drill straight holes all of the time, on many different drilling surfaces. Portable and pocket-sized, this guide block will ensure perpendicular drilling alignment, wherever you go.All blocks have alignment slots for SAILSetc standard goosenecks and metal bodied ball raced goosenecks to ensure alignment between the gooseneck and the holes. The bushing block is held at a tight tolerance and allows you to drill a hole 90° to any surface, centered on a round item or even directly into the corner of your project.

I did this so that the guide would sit against the internal corner where the upstand meets the base on the router plane. Requiring no separate guide bushes, each drill bit is guided within the hardened drill block, precision machined to the tightest tolerances to ensure 90° alignment to the workpiece.

The base body in which they are installed is usually not transparent, and only the stop for the particular application ensures the exact positioning of the drill. Once I needed to drill 4 7″ precise parallel holes on a wall based on a template and was able to do it with pretty good success by taping it to the wall.