row compacts used in the practice of the invention the blank 11 shown in fig1 includes an outer generally cylindrical jacket 13 which in this case has initially open ends 15 17 preferably the jacket 13 is formed of a suitable metal or sintered carbide which will be referred to as a 34 hard metal jacket 34 for purposes of this description although a sintered carbide such as tungsten carbide is the preferred hard metal for the jacket material it will be understood that other carbides metals and metal alloys can be utilized as well for instance other possible jacket materials include invar cobalt alloys silicon carbide alloys and the like as will be further explained the purpose of the jacket 13 in the present method is to facilitate later machining and shaping of the compact and to facilitate insertion of the compact into a cutting insert pocket on a drill bit since the jacket 13 is not the primary work surface of the compact it is not a requirement of the present invention that the jacket be formed of tungsten carbide the compact 11 has an inner core 19 of integrally formed polycrystalline diamond the polycrystalline diamond comprising at least about 10 and preferably.