Operating Instructions
3-6
HP6A Manual
During this time the machine is running unattended allowing the operator to accomplish other tasks.
Rottler does no longer recommends a single step honing process to finish engine cylinder bores.
Total honing time for a V8 block = 16 minutes.
Two Step honing:
Step One:
Abrasive: Diamond 270 Grit
Set Feed Ring to leave .0005” / .01mm maximum for second honing process. 60 Strokes per Minute.
70% Roughing Load and 30% Finish Load. When using the precision hone head you will achieve .003” /
.076mm per minute stock removal. The result is 55 seconds of honing time per cylinder. During this time
the HP6A is running unattended allowing the operator to accomplish other tasks.
Honing time for a V8 block = 7.3 minutes
Step two:
Abrasive: Diamond 500 Grit
Set Feed Ring to hone to size. 60 Strokes per Minute. 70% Roughing Load and 30% Finish Load. .
When using the precision hone head you will achieve .0015” / .038mm per minute stock removal. The
result is 24 seconds of honing time per cylinder.
Honing time for a V8 block = 3.2 minutes
Total honing time for a V8 Block with a Two Step Process = 10.5 minutes
Note:
When looking at actual honing time only, the two step process is 5.5 minutes faster than the single step
process. Because the operator must change abrasives in the two-step process 1-2 minutes should be
added for two abrasive changes. Considering the operator must position the machine in each cylinder
two times for the two-step process, the time difference between the two methods is slight. The single
step process allows for more operator uninterrupted free time.
The single step process would allow the operator to easily run two machines at one time or perform work
other than honing.
The two step process becomes more effective as the ending surface finish requirement becomes
smoother. If a 12 - 16 Ra finish was required, the honing time for a single step process would become
approximately 24 minutes and the honing time for the two-step process would remain near 10.5 minutes.
The two step process becomes more productive when more than .003 of material must be removed.
The above calculations should be made to determine the best method for the customer’s particular
requirements. Actual times will vary depending on the engine block material, stock removal required, and
the desired accuracy. The purpose of the above comparison help the user understand different methods
may be used to obtain the same result and that there is a significant difference in potential productivity
when comparing the different methods.
Using Vitrified Abrasives
Abrasive grades are available for most any finish you want to achieve. Two or three bond hardnesses
are available with most grits. The right bond hardness will break down gradually depending on the grit
used. Too soft a bond will lose abrasive excessively. Too hard a bond will chatter and start glazing the
bore, with rapid heating and poor stock removal.
Finer grit stones generally break down much faster than coarse grit does. They must break down quickly
to prevent the stone from loading or glazing.
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