When you use a lathe (vertical or horizontal) to
hone, you can mount the work in a chuck or on a
faceplate and rotate it. In this arrangement, you will hold
the honing tool in the tailstock with a chuck and use the
tailstock spindle to move it back and forth in the
workpiece bore.
When you use a milling machine or a horizontal
boring mill, mount the workpiece on the table and the
honing tool in the spindle. Move the machine table to
pass the hone back and forth in the workpiece bore.
You also can use a hand-held power drill to rotate
the hone in the workpiece. Move the rotating hone in
and out of the hole by hand.
Each of these methods requires that the hone be
allowed to self-align with the workpiece bore. To help
this process, place one or two universals between the
hone shaft and the device or spindle that will hold or
drive the hone. Hone manufacturers can usually furnish
these universals and shaft extensions.
When you hone large bores, use a device that
attaches to the hone and lends support to the stones and
guides to ensure a rigid setup.
Figure 10-32.--Stationary honing machine.
STATIONARY HONING MACHINE
Most large machine shops have a stationary honing
metals and glass. Grit sizes range from 150 to 400. If
you need to remove a large amount of metal, use a
machines are usually self-contained hones with a
coarse grit stone such as a 150-grit to bring the base to
built-in honing oil pump and reservoir, a workholding
within 0.0002 to 0.001 inch of the finish size. Then, use
device, and a spindle to rotate and stroke the honing
a finer grit stone to get a smooth finish. The hone
stones. They usually have standard controls to adjust the
manufacturer will recommend stones needed for
rpm, the rate of stroke, and the pressure feeding the
specific jobs.
stones to the desired size. Most models have a zero
setting dial indicator that lets you know when the
desired bore size is reached. Follow your machine
manufacturer's operating manual.
HONING HINTS
STONE SELECTION
Honing does not change the axial location of a hole.
The center line of the honing tool aligns itself with the
The honing stone is made somewhat like a grinding
center line of the bore. Either the tool or the part floats
wheel, with grit, a bond, and air voids. The grit is the
to ensure that the tool and the base align. Floating allows
cutting edge of the tool. It must be tough enough to
the tool to exert equal pressure on all sides of the bore.
withstand the pressure needed to make it penetrate the
surface, but not so tough that it cannot fracture and
As the honing tool is stroked through the bore, the
sharpen itself. The bond must be strong enough to hold
pressure of the grit is greatest at the tight spots. There-
the grit, but not so strong that it rubs on the bore and
fore, the hone takes out all taper and out-of-roundness
interferes with the cutting action of the grit. Air voids
before it removes any stock from the larger section of
in the structure of the stone help the coolant or honing
the bore. It also takes out any bow. Since the honing
oil clear chips and dissipate heat.
stones are rigid throughout their length, they cannot
follow a bow--they bridge the low spots and cut deeper
Honing stones have either aluminum oxide grit for
on the high spots, tending to straighten out a bow.
ferrous metals or silicon carbide grit for nonferrous
10-21