由GBl97—81知该螺纹大径为Φ30mm 所以编程大径取为Φ29. 7mm，设牙底由单一圆弧形状构成，取圆弧半径为R =1/8H =0.2.则编程小径为

    d’=30-7/4×0.866×2+2×0.2-0.038-0.17/2=27.246取编程小径为Φ27.3mm

  加工程序如下

%0005

N01 G92 X270.0 Z260.0

N02 M03 S800  

T0101

N03 G00 X35.0 Z104.0

G00 G90 X28.9

N04 G32 G91 Z-53.0 F2.0

G00 G91 X100.0

G00 Z53.0

G00 G90 X28.2

N05 G32 G91 Z-53.0 F2.0

G00 G91 X100.0

G00 Z53.0

G00 G90 X27.7

N06 G32 G91 Z-53.0 F2.0

G00 G91 X100.0

G00 Z53.0

G00 G90 X27.3

N07 G32 G91 Z-53.0 F2.0

G00 G91 X100.0

G00 Z53.0

T0000

N08 G00 X270.0 Z260.0

N09 M05

N10 M30