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Old 25-08-2018, 03:37 PM
Billyboy78 (Bill)
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Billyboy78 is offline
 
Join Date: May 2018
Location: CRESTMEAD Brisbane
Posts: 103
Feel free to say "I told you so" but I mistakenly presumed all the grits for optical and lapidary came out of the same factory. Wrong! The locally purchased grits from #40 - #400 worked great, it was the #600 and #1200 that were contaminated. Yes, I'm an idiot but I had to know. 40 yrs ago they said not to use them, but I thought things may have changed over time. Patiently waiting for some good stuff to arrive. They are only fine scratches that come out with 10 minutes of #600.

The delay has given me time to work on the mirror cell. I put the mirror into the cell for the first time and the 18 points worked great. Rather than expensive aluminium triangles, I used 1" x 1/8" metal strap welded into a T with the same dimensions as the PLOP design. The bit I worked on were the edge supports designed by Mike Lockwood using a wiffletree arrangement with tiny roller bearings contacting the mirror. I'm going to use the cell for any testing with the ke, ie sit the cell below the level of the ke so the mirror is resting on the 18 supports.
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