So one more drill point geometric parameter is needed, such as heel clearance angle, chisel edge clearance angle.
为了获得唯一的后刀面廓形，必须增加一个辅助参数。可供选择的补充参数有尾隙角、横刃后角、周边后角、切深后角等。
According to the mathematical models for flank and flute of new drill (drill point termed the non coaxial helical drill point), formulae for cutting angles of the cutting lip and chisel edge and for heel clearance angle are deduced based on their defintions.
根据钻头主刃和横刃上各种工作角度及后刀面尾隙角的定义，由新型钻尖的后刀面模型和前刀面模型推导出了各种角度的公式，为利用软件进行新型钻尖的 CAD系统开发提供了基
The Reach model is rather plain in comparison to the Birdy's, and a light/reflector bracket might be a useful addition. I would also have liked to see some cross-beams to help locate pannier hooks: as with the Birdy I'd set the Ortliebs for maximum heel clearance and found it just sufficient. But on the Reach, there's nothing to stop the panniers sliding along the rack, unless you can cunningly hook the panniers onto the lower support.
和Birdy的货架比较，Reach的确阳春了些，并未把反光片/车灯架考虑进去，是未来要注意的；此外也希望货架上能做些横档来固定马鞍袋的位置，我在Birdy的货架上固定Ortlieb的袋子没有问题，在Reach上则因为货架设计关系，除非能在下支架另外找到固定点，否则袋子的滑动问题无法避免。