The boring-bar s, furthermore, has a collar at the top and a nut n at the bottom.
This head is also driven by a key which engages a keyway in the boring-bar.
In the first operation, boring-bar m is brought in line with the spindle and is entered in bushing r in the chuck.
Next, the boring-bar m1 is brought into position, the drill support being swung back out of the way.
At the same time, the bore is finished by a cutter in boring-bar D (Fig. 4).
The spindle S which drives the boring-bar, and the spindle feeding mechanism, are carried by a saddle.
When a hole is to be bored, a boring-bar B1 is inserted in the spindle and the cutter is attached to this bar.