I ended up using a .7mm drill bit intended for drilling holes into printed circuit boards with a "pin vise" mounted in the drill press.
While this did bring me to the doorstep of success, I must admit that I'm not 100% onboard with the approach. I had picked up the idea of using a pin vise from Bill Jurgenson's fine website. Naturally, he's probably using a top-of-the-line jeweler's pin vise while I simply ordered mine from eBay hoping it would work. It did not, at least to my complete satisfaction, and here's why.
The drill bit barely fits into the end of the pin vise, so the connection is somewhat tenuous at best. It is also nearly impossible to get a perfectly straight seating of the bit into the vise, which produces a wobble no matter how carefully I try to insert the bit. At these tolerances, even a .1mm wobble results in adding that much to the hole, making it larger than intended. As much as I want it to be, this is not acceptable.
I also learned a few things about the angle of repose of the vise holding the jack body. In this case, I had set it at 10 degrees, which produced a hole that exited the back too soon (i.e., the angle is too acute). What I need is a smoother slope that allows the bit to exit farther down the opposite side of the body - something more along the lines of 7 degrees. This is required because an angle that's too sharp forces me to cut the through hole (for the PEEK filament spring) too high on the body - in some cases into the tongue divet. Also not acceptable.
In the end, I'm forced back to the drawing board and to actually take Owen Daly's advice regarding this matter - advice he gave me over a year ago. I have no idea why I don't just listen to him and do what he says. Call it a character flaw, I don't know. I can only imagine how exasperated he is with me by this time. I've been pulling this sort of thing for years and always end up just doing what he told me to do in the first place and finding success. Maybe someday I'll learn.
By taking Owen's advice, I mean that I'm now designing and building a slider with a horizontal orientation. It requires a surface mounted to roller bearings that traverse two metal rods to provide the to-and-fro motion of an equally mounted Dremel tool. Said Dremel holds the .7mm drill bit perfectly straight, providing a more stable and accurate cut. I'll be posting more about this device because I ordered the parts tonight and they won't arrive for another week (or two under present extenuating circumstances).
This whole process has been exhausting, but I must keep at it until I can produce jacks reliably and in great number. Then, I will celebrate my success and order all of my jacks from Norm Purdy in Eugene.
Until next time...