commonly used types-standard, boring bar, and
quick change-are discussed in this chapter. The
toolholder holds the cutting tool (tool bit) in a rigid
and stable position. Toolholders are generally made of
a softer material than the cutting tool. They are large
Figure 6-14.--Quick-change toolpost.
in size and help to carry the heat generated by the
cutting action away from the point of the cutting tool.
Standard toolholders were discussed briefly in
most Navy machine shops. It mounts in the T-slots and
chapter 5 of this manual. However, there are more
is tightened in place by the locknut, which clamps the
toolpost firmly in place. Special-type toolholders are
used in conjunction with this type of toolpost and are
held in place by a locking plunger, which is operated by
the toolholder locking handle. Some toolposts have a
sliding gib to lock the toolholder. With this type of
toolpost, only the toolholders are changed, allowing the
toolpost to remain firmly in place.
Lathe toolholders are designed to be used with the
various types of toolposts. Only the three most
Figure 6-15.--Standard lathe toolholders.
Figure 6-17.--Types of knurling rollers.