of hard abrasion and erosion resistant material at the smaller end 304 of wall 302 a friction weldable metallic member 306 extends axially from the wall 302 and also extends into the hollow cavity 308 within the exterior wall 302 the cavity 308 and member 306 contained therein are enlarged at the cutting end 300 to prevent separation of the wall 302 and metallic member 306 during drilling operations like the embodiment of fig1 the cutter 292 is mounted in a socket by rapidly rotating the cutter about axis 296 while the insertion end 310 is in frictional contact with the socket floor for melting softening and expansion of the deforming metal member 306 as previously described a further form of the invention which includes a screw thread is shown in fig1 through 23 as depicted in fig1 stud cutter 320 has a truncated conical cutter body 322 with longitudinal central axis 324 a preform cutting element 326 is shown fixedly mounted on the cutting end 328 of the body 322 the cutter 320 fits into a generally truncated conical socket 330 in the drill bit body 332 the socket 330 contains helical screw threads 334 on its upper portion the cutter body 322 has matching screw threads 336 on the upper conical portion for tightly screwing the cutter 320 into the socket 330 thus the threads are on conical surfaces and provide limited contact area for locking the socket depth is shown as exceeding the length of the cutter body 322 to ensure a tight fit of cutter 320 into socket 330 a key 338 is driven into a generally axially oriented keyway 340 from the bit body surface 342 to lock the cutter 320 into the socket 330 in fig1 cutter 350 has a cutter body.