Abstract: A depth stop for a drilling tool to form a hole of predetermined depth. The depth stop includes an interface portion that couples directly to the shank of the osteotome via interlocking spur and groove features. The interface has a cap flange and a tapered skirt. The underside of the cap flange establishes a reference surface for a tubular key that slides onto the tapered skirt and is held there by friction. The skirt is formed with a relief directly under the cap flange to facilitate haptic confirmation of proper connection. Elongated irrigation windows in the key expose a domed transition on the osteotome, thereby facilitating irrigation. The depth stop can be used, optionally, with an alignment jig designed with a precision guide bushing. The guide bushing is semi-cylindrical and terminates with an internal abutment step against which the lower end of the key engages at full depth.