User Guide

E ffect of Contact Wheel Serration on
Mineral We a r
Slotting the contact wheel has a unique effect on mineral wear.
Slotting acts as a self-sharpening agent. Notice the several sharp
edges on the enlarged grain used on a serrated wheel . . . versus
the flat surface of the grain used on the smooth wheel. This is
due to the fact that the grain is presented to the work at a
d i fferent angle each time it passes over the wheel.
The Serr-X Contact Wheel and Features
The Serr-X is a special contact wheel developed by 3M for
maximum conformability. The Serr-X rubber contact wheel has
a wide range of benefits. Unlike a diamond pattern, the Serr- X
does not transfer its pattern to the work. It conforms better, cuts
f a s t e r , and also lengthens the life of the abrasive b e l t .
Contact Wheel Perf o rmance
This graph shows the results of a test using four different wheels
. . . all 80 durometer. The Serr-X wheel cuts 1600 units. T h e
scoop, 1300. The standard serration, 1000. And theplain face,
700 units. A c t u a l l y, Serr-X wheels can, and should be made 10
to 15 durometer points harder than conventional wheels.
E f fect of Contact Wheel Serration Angle on
Finish
The smaller the serration angle, the lower the micro-inch finish .
. . the finer the finish. Slot angles of 30° or less are usually used
in the polishing operation.
The 90° angle often makes a siren-like sound and frequently
leaves a pattern on the work. The 45° angle is the largest one
that will still run relatively quiet. However, in operations where
the belt wrap around the wheel is less than 90,° the contact wheel
slot angle can go as high as 60° and still perform rather quietly.
E ffect of Lubrication on Abrasive Belt
E fficiency
Lubrication is another factor that can help control the rate of the
cut. Adry belt has a high initial cut, and drops off rather rapidly.
Water emulsion follows pretty much the same pattern. The film
of oil shows the best results as far as overall cut is concerned. A
flood of oil, of course, builds up an even thicker film and does
not allow full penetration of the grain; the curve, as you see, is
softer and extends the rate of cut over a longer span. T h e
greased belt really levels the curve area beneath the lines
representing stock removal.