Just to be clear, I haven't seen your article in Home Shop Machinist as of yet, Jim. I was expressing my confusion over the article that johnthefish linked to earlier in this thread. Your mechanism is constructed differently from that one as I can tell from the picture in your last post. Sorry for any confusion I may have caused you.
I did find your cross slide retractor one day when I was scouting around for projects. I really like what you've done with that as well. I have to admit that I dis-assembled my lathe in an effort to see how I might be able to apply it to my lathe. The Leblond cross-slide screw is firmly attached to the taper attachment. The operator handle is attached to the screw by means of a spline which is free to slide axially on the cross-slide screw. Thus to produce a retractor would require a reach to the far end of the cross-slide screw, or a much more cumbersome linkage/mechanism. . . . I didn't see an obvious way to work around these issues, so decided to let that one go. Perhaps I'll have to be satisfied with a retracting tool holder one day.
I put together a spreadsheet to figure out what gears I would need for the common metric sizes that I use. I believe I could get by with 24T, 30T, 36T, 37T, 42T, and 47T together with my QCGB to produce pitches 0.7, 0.8, 1.0, 1.25, 1.5, 1.5, 1.75, 2.0, 2.5, 3.0 as well as others. I hadn't yet exposed the gear-train on the Leblond when I did the spreadsheet, so I wasn't aware that there is a 48T on the spindle and a 36T on the input to the QCGB. A workaround for this would be to compound a 36T gear 48T gear after the reverse/idler gears, but that would require a second 36T gear for some of the thread pitches. I may be able to re-work my spreadsheet to eliminate that requirement. . . .
I'm not going to rush into anything. I've got a couple of other projects lined up first, and I have been able to get along just fine without metric threading up to this point. It would be nice to have, though!
Jim