Determination of time of temperature rise in a cutting tool is of significance in machining of metals. It is particularly so in milling where the cutting is intermittent, thus allowing time for dissipation of heat between successive cuts. Many researches have been directed to this problem but their findings vary widely within the range of 0-2 sec. to 20 min. It would seem that this wide variation is due to the effect of the first revolution where the feed is, in effect, continuously increased. As a result of the research incorporated in this paper, the time of temperature rise was determined, eliminating the effect of the first revolution. It varied from 006 sec. at a very high speed of 342 ft./min. to 1.4 sec. at 11.2 f.p.m.