the actual fly is tied on the B-C stem and then it seems to be clipped on to the hook once the silk tippet is tied in.
of a completely different concept but closely resembling the hook-changing possibilities we have with tube flies this is bloody ingenious and something the creative tier might want to experiment with. since we’re mostly using modern hooks with eyes, my thoughts are we needn’t bother with making clips as the stem can be simply tied in fore and aft and easily trimmed off later if needed. this also brings up ideas of being able to quickly change foam bodies or other softy materials that easily get munched to bits after a few fish but i’m sure we can think of a lot of other uses.
a little research hasn’t shown whether Upton’s patent was a lucrative one or not but this deserves some special attention. be sure to pass on his name if you give this style a go.
(more HERE on the history of hook eyes and the beginnings of the tying vise)