Operating Instructions
3-8
HP6A Manual
Improper coolant mix.
The ratio of water to synthetic additive to water will change after the initial mix is put in the coolant tank.
A Refractometer can be purchased to accurately check the ratio. When the ratio is measured as a
percentage it should be 5 – 8%. This corresponds to a reading of 3-5 on the Refractometer. It is
important not to confuse the percentage with the true Refractometer reading.
Unacceptable synthetic coolant brand.
Lack of abrasive dressing.
Dirty Coolant.
Breaking In A New Set of Diamond Abrasives
Rottler diamond abrasives are pre-radiuses to minimize the breaking in period. When a new set of
diamonds is installed the surface finish obtained on the first few blocks will be 5-10 Ra rougher than after
the break in period. You must hone 2 - 5 blocks before the surface finish stabilizes.
Dressing Diamond Abrasives
Diamond Abrasives use a metal bond to hold the individual diamond particles. Failing to dress the stones
after honing 30 - 50 blocks will increase the pressure required to remove stock or the stock removal rate
slows down significantly. This will result in finishes with excessive folded and torn metal. Undressed
stones will also cause excess bore distortion and inaccuracies in the boring process. This is caused by
the diamond abrasive dulling or the bond not breaking down. The edge of the stone will also become
very sharp. This is a normal occurrence and is easily corrected by removing the holder/abrasive
assembly, use a wire brush to dress the abrasive. A common method is to remove the stone holder from
the hone head. Leave the stone in the stone holder and move the stone through a bench grinder wire
wheel. The brush rotation should be across the narrow width of the stone. Turn the holder over and pass
the stone through the wheel again. This process will return the abrasive to a like new cutting condition,
and put a slight radius on the edge of the abrasive stick (approx. .005 inch.)
Torn Metal
This is often caused by improper coolant mix, lack of dressing, or the use of high honing pressure during
the finishing process. The Rottler hone head is capable of very high loads. If problems with torn metal
are encountered verify the coolant mix, proper dressing of the abrasives, and reduce the finishing load
during the final hone stage. If required make several strokes by hand with minimum stone pressure (10-
20%).
Stock Removal Rate
The hardness of the cylinder you are honing will affect the stock removal rate. If you find the stock
removal rate for a given cylinder is slower than normal check to make sure you have properly dressed the
stones. Improperly dressed stones can increase honing time by as 50% or more. Improperly dressed
stones will also produce an unacceptable finish.
Diameter Range
Because the diamond abrasives break down very slowly, a single set of stones is limited in its diameter
range. One set of diamonds should be used for each stone holder range. A set of diamonds can not be
constantly changed from one stone holder size to another. The stones would constantly be in the break-
in process and very poor performance or finishes will result.
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