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  #121  
Old 12-05-2019, 05:17 PM
Billyboy78 (Bill)
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Scary stuff this. Figure and smoothness getting better all the time. I'm at my target of 18mm correction but the 50% zones need smoothing. I'm using a 6" star lap to dig out the centre and a 12" star lap to smooth it out.

A metric digital depth gauge should arrive on Wednesday to replace the jerky imperial dial gauge I planned on using. Thousandths of an inch make my head spin. I plan on making a graph comparing calculated to actual zone readings.
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  #122  
Old 15-05-2019, 05:04 PM
Billyboy78 (Bill)
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I thought I could clear up the last of the astigmatism during the parabola session but it is not to be. I got the 15" lap out of storage and did a 1 hour stint with the plan to go back to a sphere, but I may not have to. I had a white and a black tadpole chasing each other across the middle of the mirror but this has come good. Fingers crossed.
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  #123  
Old 19-05-2019, 10:47 AM
Billyboy78 (Bill)
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Nah...gone back to #500grit with the old tile tool. Did 20 minutes now on to #1200.
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  #124  
Old Yesterday, 11:31 AM
Billyboy78 (Bill)
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Update....

Simply, it appears my super dooper turntable is not up to the job and I need to make a new stronger one, even though its going to be used hopefully for a very short time. This however is going to cost + time, both I don't have.

I have come up with a solution though for a cheap strong true turntable. Use a rear differential out of a car, mounted vertical with a mortar filled rim on top.
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