Alignment disks, and the creation thereof

I've though of doing it. Maybe taking a 'spare' 8" drive and replacing the postiioner with a manually-operated micrometer hrad (it doesn't matter if I have to position the head by hand for each track, I don;t need to prodcue alignment disks quickly!). I am curious as to what the 'real' alignment signals look like. One reference seemed to impley they were circular tracks not concentric with the spidnle. Making those would be 'fun'... I was given a drive exerciser (darn useful it is too...). It's a simple microcontrtoller application and a bit of TTL to generate f and 2f write waveforms (there's no read electornics in the excerciser, you use a 'scope for that). Alternitvely, some floppy drive service manuals include the schematics for the manufactuer's exerciser and a suprising number of those are just TTL chips (nothing programmable/programmed), so something similar could easily be made. Sure, ut a lot more bulky (which is an issue when I've got most of a classic ocmputer all over my workbench!). Well, I won;t admit to being a good machinist becuase I am not. I need a lot more practice. Like many things, you can read all the books there are, bnt you still need to put the time in having a go. That alas, does not suprise me. I really do wish we could get away from this idea that 'professional' is necessarily better than 'amateur'. 'Professional' means you're paid fro it , 'Amateur' means you do it because you love it. And the second may well involve more care, more attention to detail, and a better understanding of the subject than the former. (Hint : How many computer 'professionals' these days would even know what an alignment disk was, let alone be considering how to make one)? -tony