Instruction Manual
Section Five
during the set-up, allow enough room between the table and the
wheel so that the table can be swiveled to greater or lesser angles
without disturbing the slide bracket.
(b) Start the wheel (RUNNING DOWN AT THE POINT OF CON
TACT) and use the diamond dresser to true and dress the wheel to
either an open condition (ROUGHING) or smooth condition (FINISH
ING). Take no more than .001 inch off the wheel per pass, but
vary the speed at which the protractor is moved across the wheel.
2. Grinding Procedure: If the tool has been chipped or broken, or if it is
very dull (OVER .030 INCH WEAR BELOW THE CUTTING EDGE), it
should be rough ground prior to finish grinding.
(a) If the tool is chipped or broken, rough grind the steel shank below
the carbide on an aluminum oxide wheel located elsewhere, using
an off-hand method. Grind on the corner of the wheel while approxi
mating the original relief angle. Remove the steel behind the carbide
on top of the tool, if necessary, in the same manner.
lb) With the silicon carbide wheel dressed for rough grinding, grind a
relief for the end and side. The K. O. Lee wheel provided is 100
grit which is suitable for both roughing and finishing of tools for
many operations. Under some conditions, coarser grit is desirable.
If only a narrow primary land is desired, grind the secondary angle
first with the roughing wheel Keep the wheel rough dressed during
this operation by using the abrasive wheel dresser supplied with the
machine. For this operation, use only the table as a steady rest
while keeping the tool in constant motion by (i) moving it back and
forth across the wheel face, (ii) rocking it, and (iii) tipping it up
and down slightly. Grind the wheel running onto the tool at all
times. Dry grind during this process, always allowing the tool to
cool naturally. Never quench carbide in water or oil. When the
worn or broken portions have been ground away, redress the wheel
for the final roughing of the secondary or primary relief angle. Hold
the tool with light pressure against the wheel, moving it constantly.
(c) The sequence for both rough and finish grinding is as follows: Grind
the top face of the carbide first. Next, grind the side relief, followed
by the end relief. Then grind a chip breaker back of the cutting
edge if the situation calls for this. Since chip breakers require a
separate tool holding device, wheel, and procedure, this subject is
left for more detailed handbooks.
NOTE:
Tools may have either
positive or negative back rake, or none at all. Before the top face is
ground, check the side and back rake angles and set the table and
protractor accordingly so that these angles will be generated when
the tool is turned on its side and its face held against the wheel.
(d) Finish grinding is accomplished by smooth dressing the standard
silicon carbide wheel or by changing the wheel to a diamond wheel
of approximately 220 grit. The latter type of wheel is especially
desirable for finishing tools to be used on cast iron or nonferrous
metals. Keep diamond wheel clean with the use of a fine grain
silicon carbide dressing stick. If coolant is used, always keep a
generous supply of coolant running on a diamond wheel if possible,
as this will keep the wheel clean longer and reduce the chance of
cracking the carbide. Set the tilting table at a primary relief if a
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