Regular flute twist bits Have a very shallower helix angle than parabolic flute bits. To paraphrase, they may have a shallower groove as well as a smaller sized chip Room, leading to slower chip removal. They're a lot more ideal for drilling through soft elements, which include Wooden or plastic. https://beckettdcawt.wikinewspaper.com/3403563/the_2_minute_rule_for_twist_drill_bits