Roman Britain had enjoyed an abundance of simple iron goods, documented by the many hob-nail boots and coffin-nails found in Roman cemeteries.
罗马墓地中发现的许多柳钉靴子和棺材用铁钉表明，当时的英国拥有大量的简单铁制品。
2
In this paper a new simple and exact method is presented for Calculating the tooth profile of the hob cutter based on summing up the various methods for calculating the hob profile.
本文在总结滚刀齿形各种计算方法的基础上，提出了一种新的既简单实用，又精度高的滚刀齿形计算法；
3
The structure, principle and application of a simple centring device used for the sharpening of hob cutters are described.