1) DIA. 8mm Hole oblong during the machining time. |2) Drill went cross through the hole due to overload caused by blunt cutting edge.|3) MS drill was used as to carry out the hole operation the life of cutting edge was not monitored.|4) This operation was usually carried out using the Carbide drill but the tool was sent to re-sharpening during the production of this batch. Therefore MS drill was used to complete the production. |5) The availability of Carbide drill was less.