User Guide

E ffect of Contact Wheel Serration on
Abrasive Belt Eff i c i e n c y
This chart shows the effect of three different types of wheels on
belt eff i c i e n c y. The Serr-X or cross-slotted wheel removes the
most stock. Both the serrated wheels will remove a great deal
more stock than the smooth face wheel. The curves also indicate
a longer belt life for the serrated wheels and show that they
remove more stock over a greater number of sheets.
E ffect of Contact Wheel Serration on Finish
Serrated wheels do not produce as fine a finish. The more
aggressively the wheel is slotted or serrated, the rougher
t h ef i n i s h .
E ffect of Contact Wheel Area on
P re s s u r e
The amount of pressure per square inch exerted against a piece
of work will affect the rate of cut and belt life. This chart shows
how various slotted and serrated contact wheels affect pressure.
Given a total pressure of 100 pounds and a tangential contact
area of two square inches, the plain face wheel applies a
pressure of 50 psi.
Acontact wheel with a standard 1-to-1 ratio yields 100 psi. T h e
scoop serration at a ratio of 3 to 1 provides 200 psi. With a Serr-
X wheel and a 4-to-1 ratio, the pressure rises to 250 psi. In other
words, with total pressure remaining constant, the pressure per
square inch rises in proportion to a decrease in land area.
Impact Effect of Contact Wheel Slot Angle
The angle of the contact wheel slot also affects rate of cut and
belt life. The 90° or straight across slot is the most aggressive
grinding angle, and creates the highest impact on the work.
The reason is that inertia causes the workpiece to slip into the
voids and the impact of the following lands drives the mineral
deeper into the work with a very high unit pressure. Because the
45° and 7° angles give more support to the work, this impact is
minimized and the rate of cut is lessened, and so is belt wear.
One reason the 90° slotted wheel emphasizes belt wear is that
the belt gets more flexing with the 90° serration. This results in
the shedding of larger grains and faster shedding of working
grains. Noise and chatter are other reasons why the 90° slot is
seldom used.