from each other so that the crest is not of uniform width the inner row inserts 41 42 are generally chisel shaped and have a special configuration as shown in fig2 through 4 the inserts of inner rows 41 42 have a cylindrical base 43 which is inserted in retaining hole 33 with its longitudinal axis 45 being normal to the surface 47 of cutter 15 a cutting tip 49 is formed integrally with a cylindrical base 43 and protrudes outwardly from cutter surface 47 the cutting tip has two faces or flanks comprising a leading flank 51 and trailing flank 53 flanks 51 53 commence at the joinder of the cutting tip 49 with the top 56 of base 43 and converge in a crest 55 adjacent and connecting each flank conical surfaces 57 59 extend from the junction of the cutting tip 49 with the top 56 of base 43 to the crest 55 as shown in fig2 these conical surfaces incline inward or toward each other approximately 15 u00b0 from the vertical 34 vertical 34 is defined herein to be parallel with the longitudinal axis 45 the corners 61 63 of the crest 55 at the junction with the conical surfaces 57 59 are also rounded as is apparent from fig4 the flanks 51 53 are asymmetrical with respect to each other a median plane 65 passing through longitudinal axis 45 divides the crest 55 in.