尽管许多制造商采取了切削部份与锥柄分别用不同材料制造的组合结构和其它措施来降低制造费用,但直径大于50毫米的麻花钻的价格仍然相当昂贵。尼日利亚的阿玛杜贝罗(Ahmadu Bello)大学机械工程系研制成功一种简单的可调麻花钻头,大约可以代替12种不同规格的普通麻花钻。其直径范围为52—64毫米,由钻头本体、两个刀夹和一块固定的中心刀片等4个基本零件组成,如图1、2所示,钻头本体用碳钢制造,切削端淬火,另一端为锥柄和扁尾。两个 Although many manufacturers have used cutting structures and combinations of taper shanks made of different materials and other measures to reduce manufacturing costs, the price for twist drills larger than 50 mm in diameter remains quite expensive. A simple, adjustable twist drill was developed by the Department of Mechanical Engineering at Ahmadu Bello University in Nigeria to replace roughly 12 different general twist drills of different sizes. Its diameter range of 52-64 mm, the drill body, two knife holders and a fixed center blade and other four basic components, as shown in Figure 1,2, the drill body made of carbon steel, cutting end quenching, and the other One end of the taper shank and flat tail. Two