Abstract: On the bases of the testing data, the effect of the built-up nose on the cutting force and temperature, the frequency of the built-up nose in the forming and tearing process are discussed in this paper. The connection of The built-up nose with the phenomenon of the flakes in the surface of the work-piece is particularly analysed. Through testing it is noted that the formation of the built-up nose results in the decrease of cutting force and temperature, but the formmer effect is larger. It is also noted that the frequency to the built-up nose in the forming and tearing process is high enough As to the tearing of the large part of the built-up nose it reaches 20 -120C/S. It is considered that the built-up nose is closely connected with the phenomenon of the flakes in the surface of the work-piece. The process of the forming flakes has been discussed. The metal in the low layer of the chip, producing serious stagnation is regarded as the procedent conditon. The built-up nose is the most serious stagnation, in this case the phenomenon of the flakes is also obvious. To avoid the flakes the built-up nose should be eliminated. The author found that in the condition of the forming discontinuous-type chip there also obviously exists the phenomenon of the stagnation, even the built-up nose was found. Thus the author considered that in all cases of the forming discontinuous and continuous-type chip the cause of forming flakes has no distinction in nrinciple. Hence the author throws doubt upon this point of riew in which the flakes was regarded as a particular phenomenon independent of the built-up nose.