MACH 118: Lathe & Mill I
Thaddeus Stevens College of Technology
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

For lathe work, cutting tools must be supported
and fastened securely in the proper position to
machine the workpiece.
◦ There are many different types of toolholders available
to satisfy this need.

Anyone working with a lathe should be able to
select the best toolholding device for the
operation performed.
Created by R. Schwartz 10/04/08
OBJECTIVES
OBJECTIVES:


Identify standard, quick-change, and turret-type
toolholders.
Identify toolholding for the lathe tailstock.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

An important aspect of lathe toolholding is rigidity.
◦ If tool bits or inserts are not well supported or overhang is
too great, vibration & tool chatter will often be the result.

Tool posts are mounted on the compound rest and
held securely by a T-bolt.
◦ The most commonly used
are the quick-change types,
more versatile than the
standard post.
Fig. I-48 Quick-change tool post,
dovetail type.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

The tool post shown here uses double vees to locate
the toolholders, which are clamped and released from
the post by turning the top lever.
Fig. I-49 Quick-change tool post.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE
•The quick change tool post (Aloris) has replaced
the now obsolete “rocker” type tool post.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

Toolholders for the quickchange tool posts are made
in many different varieties
to accommodate various
machining ops.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

A boring bar toolholder in use; the
boring bar is rigidly supported.
Fig. I-54 Boring toolholder. This setup provides
good boring bar rigidity (Aloris Tool Technology)
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

A cutoff tool mounted in a toolholder.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

A tailstock spindle used to hold Morse taper
shank tools
Fig. I-62 Taper shank drill with
sleeve ready to insert in tailstock
spindle.
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE
• One of the most common toolholding devices
used on a tailstock is the drill chuck
– Used for holding straight shank drilling tools.
Fig. I-63 Drill chuck
with Morse taper shank
Created by R. Schwartz 10/04/08
TOOLHOLDERS/TOOLHOLDING FOR THE LATHE

When a series of operations must be performed
and repeated on several workpieces, a tailstock
turret can be used.
◦ The tailstock turret shown
has six tool positions.
◦ One is used as a workstop.
◦ The other positions are
for center drilling, drilling,
reaming, counterboring,
and tapping.
Fig. I-64 Tailstock turret.
Created by R. Schwartz 10/04/08




Name two different types of toolposts used on
engine lathes.
Which type of toolpost has become obsolete and is
rarely used in industry?
State some advantages of the quick change
toolpost.
What type of taper is found in the tailstock spindle?
Created by R. Schwartz 10/04/08