Saturday, May 23, 2009

Errata corrected

In examining my mirror cell, I found a couple of minor problems I overlooked. The aluminum triangles were turned the wrong way, so I had to drill and tap another hole in them and do the same to the plastic ring to keep them from turning. I drilled out the original slots with a 3/4-inch Forstner bit and made a new slot for the screws.

The other problem was that the eye bolt mirror clips would not tighten down securely. I couldn't find eye bolts that would fit tightly around the threaded rod, so I used the smallest size stainless steel eye bolts I could find. Evidently, they weren't small enough so I took some left over pieces of 1/2 by 1-inch aluminum bar and made mirror clips from them. With a rubber bumper pad added and stainless steel flat washers, lock washers and hex nuts these clips stay put and the mirror will never contact metal. I sanded and painted the fan board with flat black paint. I was originally going to varnish it, but decided against it since I will be putting a LED on it that will be lit when the fan is operating. The fan itself was bought from a local electronic supply store and it was attached to the fan board with stainless steel pan head screws, nuts and washers. I put it in the inside of the board to keep it from bumping the bottom of the rocker box or the azimuth encoder for the digital setting circles that will be on the pivot bolt.

I made a dummy mirror and installed it in the cell to see if the mirror will fit correctly in it when I receive it. It does not contact metal even as I move it around in the cell, though it does stop only 1/8th of an inch from the split bolts. I may replace the eccentric side pins with bigger ones but I anticipate once I wrap the sling around the split bolts the risk of glass crunching collisions with them will be eliminated.

Complex as this cell is, it's easy to take apart and repair. The mirror cell is now complete, and now that a cooling fan has been added to it, I will begin making the upper end assembly. The total weight of the mirror cell is now between 12 and 13-pounds, and the mirror it will contain will weigh about 25 pounds.

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