Tc 9-524 fundamentals of machine tools

Grinding Feeds, Speeds, and Depth of Cuts
Rotate the work at a fairly low speed during the grinding
operations. The recommended surface foot speed is 60 to 100
FPM. The depth of cut depends upon the hardness of the
work, the type of grinding wheel, and the desired finish.
Never take grinding cuts deeper than 0.002 inch Use a fairly
low rate of feed, You will soon be able to judge whether the
feed should be increased or decreased. Never stop the rotation
of the work or the grinding wheel while they are in contact
with each other.
7-65

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TC 9-524
Marking Position of Lathe Centers
Tool post grinders are often used to refinish damaged
centers. If the lathe is to be used for turning between centers in
the near future, grind the tailstock center first, then the
headstock center. Leave the headstock center in position for
the turning operation. This method provides the greatest
degree of accuracy. If you must remove the headstock center
in order to perform other operations, marks placed on the
headstock center, the sleeve, and the center will enable you to
install them in the same position they were in when the center
was ground. This will ensure the greatest degree of accuracy
for future operations involving turning work between centers.
Setup for Grinding Lathe Centers
Grinding Lathe Centers
lathe
Start the grinding motor. Turn it on and off alternately, but
To refinish a damaged lathe center, you should first install
headstock and tailstock centers after ensuring that the spindle
holes, drill sleeves, and centers are clean and free of burrs.
Next, position the compound rest parallel to the ways; then,
mount the tool post grinder on the compound rest. Make sure
that the grinding wheel spindle is at center height and aligned
with the lathe centers. Move the compound rest 30° to the
right of the lathe spindle axis, as shown in Figure 7-40. Mount
the wheel dresser, covering the ways and carriage with rags to
protect them from abrasive particles. Wear goggles to protect
your eyes.
let it run a bit longer each time, until the abrasive wheel is
brought up to top speed. Dress the wheel, feeding the grinder
with the compound rest. Then move the grinder clear of the
headstock center and remove the wheel dresser. Set the lathe
for the desired spindle speed and engage the spindle. Pick up
the surface of the center. Take a light depth of cut and feed the
grinder back and forth with the compound rest. Do not allow
the abrasive wheel to feed entirely off the center. Continue
taking additional cuts until the center cleans up. To produce a
good finish, reduce the feed rate and the depth of cut to
0.0005. Grind off the center’s sharp point, leaving a flat with a
diameter about 1/32 inch. Move the grinder clear of the
headstock and turn it off.