Rottler HP 7A - Erratic Finish Sizes

Section 7 Troubleshooting HP7A Manual
www.rottlermfg.com
7-3
Possible Cause: Tapered Stones.
If your over stroke is set correctly use a micrometer to measure the stones. When measuring the
stones, measure the top of one stone to the top of the stone across from it. Record this reading and
then measure the bottom of the same stones. If the bottom of the stones measure out smaller than
the top, this will also create taper in the cylinder.
Possible Cause: Incorrect Pressure settings.
It is possible to set the Rough and Finish load setting improper for a certain type of cylinder. If there
is very little support around a cylinder, using a high rough setting can cause the walls of the cylinder
to push out while honing, and then to come in when there is no longer pressure on the cylinder wall.
This would create a hour glass shaped cylinder. You can account for this by lowering the rough and
nish settings. A lower rough setting will not push the walls out as much. A lower nish setting gives
the hone head additional time to remove material from the block to straighten it.
Possible Cause: Diamonds need dressing.
For diamond dressing instructions refer to page 3.8 of this manual.
Erratic Finish Sizes
If the hone is not maintaining size from one bore to the next.
Possible Cause: Hone Head not connected properly.
The most common cause of erratic cylinder size is a wrong connection between the Driven Coupling
(514-6-44) and Coupler Sleeve (514-6-41). When changing the hone head and yoke be sure not to
put any upward pressure on the cone (514-9-7A ), this will cause the driven coupling not to engage
correctly with the coupler sleeve. When not engaged correctly the driven coupling can move around
and cause the stones not to feed out correctly.
Possible Cause: Fluctuating Power.
If the incoming power to the machine is uctuating more than 10 volts AC, it will cause the load
display to uctuate. Since the machines stopping times are set on the load value this can cause size
variance. The power company can usually monitor the power and make recommendations for xing
the problem.
Possible Cause: Spindle Speed Changes.
Changing the spindle speed between cylinders will increase the load on the motor and thus the
machine will shut off at a different size. Do not change the spindle speed between bores.