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Old 23-10-2018, 05:46 PM
Billyboy78 (Bill)
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Billyboy78 is offline
Join Date: May 2018
Location: CRESTMEAD Brisbane
Posts: 103
It would seem the fixed post doesn't like fast mirrors. I think Logan found this out also. Yesterday afternoon I worked for several hours on the 8" with the 6" tool to deepen the centre with #220 using a variety of overhang settings, but without success. Sag went down to 3.6 mm but no further. Then I resorted to manual grinding with #80 using very short strokes COC, small W's and anticlockwise circular motion against the flow of the turntable. So, after a couple of hours we are down to 4.12 mm with a target of 4.5 mm. Pretty pleased with that. Downside is I'll have to finish of the mirror manually including polishing.
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