diagrams show the position of the centre of the mirror as it travels across
the tool. The mirror is on top. Before parabolizing the mirror and tool
should be cold pressed to ensure good contact between the mirror and the
tool. The mirror (blue) is placed in the upper position. The stroke is
much greater than normal. after each passing of the mirror turn the mirror
slightly and move to a different position around the post, this will ensure
that the surface is a circle of revolution. For a 6 inch F8 mirror
test the mirror after 10 minutes work to see how the figuring is proceeding.
Testing may reveal that the middle requires deepening.
this is achieved by concentrating the polishing action on the centre of
the mirror. the centre of the mirror is worked on the edge of the
tool as shown in the diagram. Go carefully this stroke so as to not go
The testing may show that the edge is to short. Move the mirror over the tool with large strokes as shown.
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