that it has a circular periphery 22 which forms a press fit with the circular hole 18 if through chance circular hole 18 is the same as the outside diameter 22 of the plug 20 no machining will be necessary it is necessary upon the first assembly step that the radial face 24 is smooth and flush with and in the same plane as the radial face 14 if the plug 20 is machined so that there is a flange 26 the flange 26 is formed so that it holds the plug in place with the radial faces flush as described the lock plate 30 has cylindrical portion 32 it may be considered to be a circular plate with two ears 34 projecting from it the circular portion 32 has a diameter larger than the circular hole 18 through the gear but the outer diameter of the circular portion 32 is far less than the pitch diameter of the gear teeth 16 the lock plate is placed upon the radial face 14 of the gear plate 12 so the circular portion is co axial with the gear plate although it should be co axial precision is not necessary on attaching it after it is in place it is welded by weld 36 which is located along an arc opposite the ears 34 the arc of the weld metal is no greater than half the circumference of the circular portion i e at least half of the lock plate which would be a fourth on either side of each ear is not welded to the gear therefore the lock plate may spring and be clamped to the hexagonal shaft when in.