Tool setting (Drawing No. 4C-6)
The tool setting micrometer (a) is fitted into the holder (b) and fixed to the boring spindle by means of the screw (C) .
 
Next the contact point of the micrometer is placed against the measurement point (a) on the boring head, and the micrometer as well as the dial gauge are set to zero.
 
For tool setting we now start from the basic dimension of theboring heads, viz. 1.75", 2.35" and 3.55" (46,60 and 90 mm) . See fig. 1.
 
The difference between the desired diameter of the cylinder (D) and the basic dimension (B) is the actual dimension (X) at which the micrometer has to be set.
 
When setting has been made, the boring spindle has to be turned so that the cutting tool (12) points against the tool setting micrometer. See fig. II.
 
By means of the screw (e) the cutting tool is adjusted until the dial points at zero, whereupon the cutting tool is secured by means of the locking screw at the side of the spindle.
 
If the difference between the desired cylinder diameter and the basic dimension of the boring spindle used, is bigger than the range of the micrometer which is 2" (50 mm) ，the gauge block (f) which has a length of 3/4" (17.5 mm) must be used.
 
As. shown in fig. III, the gauge block is guided by a holder (g) which has to be fitted on the micrometer. When set at zero, the basic dimension (B1) will be equal to the basic dimension (B)
of the, spindle plus 1.1/2" (35 mm)，whereupon the gauge block and its holder can be removed, and setting of the cutting tool is then made in the way described above.