| 摘要 |
A fluted screw tap has a plurality of thread lands each with a pair of outwardly facing flanks. Each flank of a pair has a different asymmetric relief ground flank surface extending in a spiral form along the length of the thread land. Each thread land has a corner resting against the cut thread. Each of the flank surfaces in a pair has a different relief grinding angle extending along the threaded flank and the angle approaches the zero value at the end of the thread land where the corner resting against the cut thread is located. |
