Real life has a way of interfering with one’s plans. When I started this project, I didn’t anticipate how much upcoming events would impact my time. But impact they did, to the point where I haven’t touched my mirror in almost a month, and don’t expect to start pushing glass again for at least another week. This is the way of things. For the curious, here’s are some valid reasons for shelving your mirror grinding project: Your mother-in-law is getting … Continue reading →
Not much to report. I put in an hour’s grinding, one third stroke centre over centre, using the #220 grit, and STILL haven’t restored the bevel. I’m playing with fire by putting that off… Under the magnifier, the surface looks much the same – it isn’t obvious that there are fewer pits than before, except for one thing: The pit density at the centre is about half that at the edge. Since the grinding technique always causes more wear at … Continue reading →
There’s something marvelous about moving on to the next finer grade of grit. The long work building up to it means there’s a huge sense of reward. The careful clean-up process gives it a sense of occasion. The different feel and sound of the grinding gives it novelty. I love it! So I recently got tired of the relentless grinds which seemed to make no progress. I was producing a beautifully smooth, spherical surface, but not gaining any depth. My … Continue reading →
Last night I sat down in the lounge with my mirror and declared war on the shape. It was beautifully spherical, and too shallow, and had stubbornly refused to deepen measurably. So I sprinkled some #120 grit onto the tool, sprayed it with a mixture of water, dishwashing detergent and glycerin, put the mirror on top, and began grinding with new savagery: As much pressure as my arms could sustain, 1/2 length strokes in a wide W pattern. After about … Continue reading →
Between 24 and 26 February, I put in two hours solid grinding (still with #120 grit using 1/3 strokes). At this stage, I’m trying to shorten the focal length of the mirror, so that the end result will fit in the boot of my car. There’s no point in making a telescope that isn’t practical enough to get used, after all. Frustratingly, after these two days, I’ve measured precisely zero progress. I’ve used both the spit test to measure radius … Continue reading →
