In the textile industry, new staple yam manufacturing systems are aiming at higher production rate and better product quality. Most of all, many recent researches are focused on improving the yam qualities by introducing new accessory devices which lead to finer and more uniform staple yam, in which the working principle is to diminish the loss of staples in forms of edge fibers at the spinning triangle. This paper deals with developing a new method that can produce more uniform yams, while using the conventional ring-spinning method. The leading ends of the staples on the same line of the front roll cylinder are grasped by the draft rolls with a certain phase difference in nipping time, to which we refer as the nipping time delay method. The nipping time delay is realized by introducing grooved front roll cylinders with various groove angles. Then, we identify the effect of the new method on the yam irregularity and also try to find the optimum condition for minimizing the yam irregularity. Experimental results confirm that the groove angle of the front roll cylinder influences the output yam uniformity and yam hairiness. There also exists an angle range between 7 to 10 degrees that minimizes the yam irregularity