An improved diamond coated bit tip insert (60) for a unitary bit/holder, tool, and/or pick for road milling operations that includes a body including a tip (62) and a base (66) subjacent to the tip. The tip of the bit tip insert includes a substrate (63) and an overlay (76) on an outer surface of the substrate. The base of the bit tip insert includes a tapered sidewall (68) or a cylindrical sidewall, the tapered sidewall providing a greater concentration of force applied at an interface of the overlay and the substrate of the tip during a high pressure high temperature (HPHT) process than when using the cylindrical sidewall and the high pressure, high temperature process.