Superb Brian, this one's even above your "normal" (i.e. very very high) standard I think.
Sorry to hear of your medical problems mate. I'm having similar "adventures" (to add to my "standard" back problems) which have pretty much kept me out of the shop and off here for a while now, so I know how you feel. Terribly frustrating.
But I have been experimenting with a couple of ideas for rounding off, etc, of small bits. May take a while yet but I'll post something that may help asap.
Thanks for posting, an inspiration to duffers like me (even though I'm not much of a bike fan at all).
AES
AES