| 摘要 |
A drill string rod to form part of a drill string having one end configured with a male spigot portion (108) to be received within a corresponding rod female sleeve end. To minimise stress concentrations within the threaded male and female coupling, the male spigot (108) is configured with a large diameter or cross sectional area being at least equal to the cross sectional area or diameter of the main length section (101). |
