a one-inch diameter drill even if one could be obtained that would fit. However, holes of even larger diameters can be accurately bored to size with a little patience and care.
FIGURE 15-Boring Head and Boring Tool. P/N 3061 is for 1/4" (6.4mm) min.
diameter by .60" (15.2mm) max. depth hole. P/N 3063 is for 5/16" (7.0mm) min. dia. by 1.0"(25mm) max. depth hole. Both have a 3/8" diameter shaft.
Boring heads work on the same cutting principle as lathe boring, except that the cutting tool turns while the work remains stationary. (In the case of a lathe, the work turns and the cutter remains stationary.) The boring head is designed to employ cutting tools with a 3/8" shank. SHERLINE offers two boring tools with lengths appropriate for the SHERLINE mill. It is sometimes advisable to remove excessive tool shank length from standard (non-SHERLINE) 3/8" boring tools in order to improve rigidity. (See Figure 4 for a boring tool in use.)
Tool sizes are listed indicating the smallest diameter hole that can be bored and the maximum depth that can be cut. For best results, use the largest diameter possible with the shortest lengths. A .010" cut represents a good starting point.
If boring a hole where a flat bottom is required, it is advisable to stop the down feed at about .002" above the desired depth, turn off the motor and cut the remaining distance by hand turning the spindle to eliminate any possibility of chatter.