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Wheel
Angle
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Figure 5
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Standard
cutters offered in most hardware stores have
wheels honed to 120' or 124'. This is a good
angle for glass ranging in thickness of .063"
to .093".
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While
flaking can occur with any wheel, sharp angled wheels
(under 120') are more prone to cause this situation.
Flaking can be avoided by wiping the score line before
scoring with a cloth dampened with a score protection
fluid such as kerosene or light oil. It is important
to try to avoid the incidence of flaking because the
character of the fissure is affected when flaking occurs.
Flaking develops a tendency to chip when the breakout
is made. While flaking does occur when sharper wheels
are used, it is often necessary to use such wheels in
cutting thin glass. In these cases, a score protective
fluid must be used.
To
determine the best wheel angle to use for a specific
glass, the procedure is:
1.¾Start
with any cutter, say a standard 120' wheel.
2.¾Score
the glass, using the maximum non crushing force.
a.¾When
thin glass is used, if the wheel punctures the glass,
then use a sharper angled wheel. The maximum non-crushing
force will be less.
b.¾If
an apparently good score is made but a good break out
does not result, use a higher angled wheel. The maximum
non-crushing force will be greater, but a deeper fissure
will be made.
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Verticality
of the cutting wheel must be maintained in
scoring. When the cutting wheel is tilted,
the angle presented to the glass changes and
affects the quality of score. With a tilted
wheel, external angle A [fig 5] is that which
would be presented to the glass by a higher
angle wheel. External angle B is that which
would be presented by a sharper wheel. The
applied force is insufficient for one side
(A) and excessive for the other side (B).
This results in gouging and a very poor and
weak edge.
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Wheel Tilt
Summary for Scoring
In
summary, the requirements for good scoring
are:
1
¾A
good cutter.
2.¾A
firm flat support for the glass.
3.¾Clean
glass.
4.¾Clean
cutter.
5.¾A
score protective fluid on the glass,
6.¾Not
tilting the wheel.
7.¾Uniform
application of force and speed: The maximum
non crushing force.
8.¾Running
the cutter off the edge at the end of cut.
9.¾A
score clean of glass chips and barely visible
when looking at the surface of the glass.
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The Break Out
Having
made an excellent score, you can still fail in the objective
of achieving a good strong edge. This can occur at break
out because the amount of bending required to break
out a score is very, very small.
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Break out at Minimum Angle
The
break must always be initiated at the edge
where the cutting score ended.
The amount of bending can be controlled
by using an anvil less than 1/16" high;
1/32" would be even better. If the cut
is run by hand or with cut running pliers,
hold the amount of bending to the barest minimum.
If the breakout is made too fast by bending
excessively, chipping cannot be avoided.
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Example 1
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Break out at Excessive Angle
The
minimum break out angle must be maintained
whether the break method used is cut‑running
or snapping.
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Example 2
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