Far more useful than its compact one-piece design might suggest, this simple guide block lets you drill holes that are both precisely placed and accurately set at 90 deg without a drill press.
To use it, just line up the drill bit with your mark and butt the guide up against the bit, flanking the bit from two sides with one of the V-notches in the guide. As you begin to drill, the notch stops the bit from skating on the surface, keeping it centred on your mark. It also ensures that the bit remains held at 90 deg, much better than even the most steady-handed woodworker can accomplish free hand.
Made of case-hardened O1 tool steel to resist wear from contact with spinning drill bits, the 44mm (1 3/4") diameter guide has knurled edges for grip and two notches – one 22mm (7/8") tall, and one 13mm (1/2") tall for use with shorter bits. You may be surprised how much your drilling accuracy can benefit from less than an inch of bearing surface.