A Study on Straightness of Deep Hole in Small-Diameter Drilling of Stainless Steel

This paper describes influence of the cutting conditions on the hole shape accuracy in deep-hole machining of stainless steel with small-diameter drill. The drilling tests were carried out by changing the step feed, the rotational speed and the feed rate in order to investigate the relationship between the straightness of the hole and the cutting conditions. As a result, it was found that the thrust force decreased with a decrease in the step feed amount and accordingly the straightness was improved. By changing the drill in incremental step from short drill length to long drill length, the straightness was improved.