Figure 3-6. Bulkhead metering valve adjustment.
3-20.
Lubricator Fitting Adjustment
a.
Back off check nut on the metering valve (fig.3-
6) and turn the adjusting screw in until it bottoms in the
valve seat to shut off the oil supply.
CAUTION
Excessive
tightening
of the adjusting screw
will wedge the plunger
into
the
metering
valve and damage the
plunger.
b.
Activate the rock drill (para 2-5) until the drill
engine has warmed up sufficiently to produce an oil film
at drill engine exhaust port and on the shank of the
striking bar.
c.
With the drill engine thoroughly warmed up,
quickly retract the drill to force the hammer to operate on
cushion. If the lubricator fitting adjustment is correct, the
drill will diesel one or two cycles. This indicates that oil is
reaching the front end. If instead, the drill continues to
sputter for many cycles when retracted, the drill is
receiving too much oil and is dieseling heavily. Too
much oil may cause the drill to overheat and force of
combustion may even drive the piston against the valve
seat. If the drill is not receiving sufficient oil, no dieseling
will occur when the drill is retracted. There will be no
occasional sputter when hot and no random dieseling or
very little show of oil at exhaust and striking bar.
d.
Adjust the lubricator fitting as illustrated in figure
3-7.
3-9
