be inhibited to promote increased operation of such drill bits to this end seal 28 is disposed between the lubricated bearing surfaces and the abrasive particles in the environment of the well bore referring now to fig2 there is depicted a larger scale drawing of seal 28 which is useful in disclosing the construction and operation of the novel seal of the present invention known packing ring seals in the prior art fall generally into two categories first a so called 34 shaft 34 seal which is disposed in the concave portion of the roller cutter or on the surface of the support shaft and compressed therein 34 shaft 34 seals are compressed radially with respect to the shaft and provide reasonable accommodation to axial displacements of roller cutter 10 the second category of packing ring seals is the so called 34 face 34 seal wherein the seal ring is disposed on the face of the cutter support and is compressed between the face surface of the cutter support and the surface of the roller cutter 34 face 34 seals provide a reasonable accommodation to radial displacement of roller cutter 10 to the limits of compression and expansion of the seal ring material seal 28 of the present invention is a hybrid form of seal which combines the advantages of 34 shaft 34 seals with the advantages of 34 face 34 seals seal 28 is comprised of a first bearing surface 30 which is formed at the intersection of shaft 14 and face surface 22 and which is disposed circumferentially about the base of shaft 14 a second bearing surface 42 is machined into roller cutter 10.