Tool assembly for repairing and in particular grinding a tap seat

A tool assembly for repairing and in particular grinding a tap seat, comprising a cutting tool carrier shaft, a guide carrying said shaft and an adapter carrying said guide, the adapter having an end portion forming a replica of the tap head normally associated with the tap body, with a screwthread which is complementary to that of said tap body, said end portion having mounted thereon a casing member comprising a screwthread for fixing and forwardly moving the guide, comprising a skirt portion with, at a terminal part, a thrust bearing for the tool carrier shaft, and having in its interior a screwthread capable of co-operating with said fixing and forward feed screwthread, the tool carrier shaft extending beyond the bearing to the operating means provided at its free end, characterised in that the thrust bearing comprises a double-acting ball-bearing thrust means whose outer race is fixed with respect to the guide while the inner race is fixed with respect to the tool carrier shaft which is arranged for that purpose, thereby to provide for axial fixing without play of the tool carrier shaft with respect to the guide, and further characterised in that at the same time the radial guiding action in respect of the tool carrier shaft is provided by means of at least one anti-friction ring which is broached after being force-fitted into one or other of the end portion-casing member components.