Abstract: A drill jig for making a channel in a timber for containing flowable preservative comprises a body (10) having a first or perpendicular guide bore (20), a second or oblique guide bore (22) and a third or vertical guide bore (24). The guide bores (22) and (24) intersect in a cylindrical locating spigot (18) and the axes of the guide bores (20) and (22) intersect in the timber to be drilled. A collet (26) on the shank of the drill bit (28) limits the depth of penetration by the lower face (32) of the collet abutting an abutment face (34) on the body (10). The depth of pentration when using the guide bore (20) or (24) is limited by the collet (26) coming into abutment with an adjustable stop (38) on the body (10). No adjustments are necessary as between drilling perpendicular or oblique bores and it is ensured that the bores formed in the timber intersect to form a continuous channel for receiving flowable preservative.