I don't have a lathe - machined on table. Woods: Aspen (I think) and Cherry. For the Cherry used in my Part 2 post and the nuts/bolt heads, I oriented the grain parallel the X-Y plane. The Cherry did great, and the Aspen was almost as good. For the Aspen, I oriented the grain of the male part parallel to the Z axis as an experiment. I'm still not sure which is stronger.
Again, Rountree's gadget works perfectly. I tried to make it more difficult than necessary. (Obviously, I don't follow directions well.)
Material size. I wanted to maximize depth of cut/ length of tube. I estimated I could jog the bit over a blank approximately 5" in the Z axis. The bit fit, but when my ShopBot jogs to Home, it raises 1" above the blank's surface. That exceeded my machine's Z axis limit. So, I changed to a 1.5" fly cutter and milled the blank down to 3.5" or so. There's probably a workaround, but I haven't investigated yet.
Cutting cylinder/holes. After running the gadget, only one toolpath is created. I kept looking for a separate toolpath for cutting the cylinder/hole. Instead, the vector is a solid pink line/circle that shows up when selected in the 2D page in Aspire. Using that solid line, run the profile toolpath (inside for female and outside for male cuts). It works - no need to try to tweak anything yourself. Then, run the threads toolpath that shows up in the Toolpath List using the Magnate bit. Be sure to widen the in/out profile cuts to accommodate the width of the Magnate bit's side cutters.
Lack of chatter. I used a fairly long 0.5" upcut spiral bit: HTC 170-2500, CEL 3" and OAL 6". So, I went slow - I think - plunge 1", feed 1", RPM 9000.
Location on blank. Rountree's instructions state that your initial circle vector merely provides the Threads gadget with a center point -- your circle is not part of the threads calculations - it does not auto-populate anything in the gadgets form. You enter the pitch size in the gadget form. Just like he says.
Mind the gap. I have not removed the bottom portion of the Magnate bit - the part that accepts the bearing assembly. (I did remove the bearing and retaining screw.) So, I left extra room at the bottom when making the threads cut. Rountree clearly provides this warning as well.
For the "bolt," I decided to mill the heads separately, adding a pocket for the finished threaded cylinder. Then, I glued the two together.