Originally I wrote...
Andrew Davie wrote:My Nipkow disc from Peter Yanczer arrived today! Here are my candid first impressions... this looks to me like a second-hand disc, which is not what I expected. Not that I'm unhappy with it, but it's not the shiny thing I had anticipated. The center label is a bit torn/scuffed, but I would probably have removed it anyway, and the hub looks a bit beat about -- a few dings, etc. Having said that, I must point out that Peter kindly added a couple of suitable cassette motors for me, which I much appreciate.
That was a fair enough call, I think -- but let's have a look at the actual results of using the disk (with reference to the attached image)...
1. The bottom of the image is a near-perfect straight line. This indicates to me that the angular separation of the holes is spot-on. Not just very good, but excellent. I couldn't ask for any better.
2. The spacing (horizontally, or radially, if you wish) is very good. There is only one 'gap' in the image, and it is a very minor one (indicated in the picture attached).
3. The hole size/consistency. Perfect. There are no apparent brightness changes caused by differing hole sizes.
4. Balance. This disk is superbly balanced, insofar as when it is rotated on the hub it appears to be spinning perfectly around a centerpoint (ie: not offset). I'm quite impressed at how accurate this part of the manufacture is.
5. Flex. Average. The disc tends to want to flex into one of two positions (in other words, it would not lie perfectly flat on the table. This was one of my main concerns originally -- but in actual usage it makes no detectable difference. There is some slight 'wobble' if you look at the disk edge-on when it is spinning, but I can see no artifact of this when viewing the image. So, although this flex/buckling nature is not something I particularly like, it makes no difference whatsoever to the image.
6. Finish. I still think the disk has a secondhand look, as noted before. I won't dwell on this point, as I'll probably paint the disc with a matt black anyway.
So there we go. Mechanically this is a superb Nipkow disc. Definitely far better than anything I could make by hand. Cosmetically there are some minor flaws -- but with the benefit of hindsight, I wouldn't hesitate to purchase the same from Peter again.