Hi Bill,
I started with an optical and machined the cogged aluminum ring for it, but couldn't get a steady rpm. In hindsight it was probably that I was grounding the cable. When I spoke to the MAcTach designer, he said the optical works well, but the height setting given in the manual is critical. Too close or too far, and it will not work. He recommended the black tape and some of the reflective tape at evenly spaced intervals (which was missing on mine). I ended up with the hall sensor and some magnets, very stable readings. If I were to do it again, I would make a round aluminum ring, bore some small holes for the round magnets and glue them in with epoxy. So it was a learning experience.
PBA 8", that a big (bad) boy, really depends on what stock you normally use, otherwise use an 8" independent if infrequent. I did some square stock the other day, so had to switch it out to the independent, but had the vibration issue. I think a good QCTP makes a world of difference, but it is always a finical dilemma. Just get the QCTP alone if it is the Dorian, not the package. I like most of the Aloris holders better.
On another tangent, these tool cabinets from HF are great for all you tool holders, etc. I use one on the side of my mill and another for the lathe (you do need to add some wheels on the bottom), they are a good size and height for frequently used items. I also place stuff on the tops that I am actively using (indicators, holders, etc.). Good price and decent quality, just do not like the shiny red on the new ones. Won't fit most chucks, but I have seen people use square weld tubing platform between the cabinets to make shelves for the chucks and heavy tooling storage (also adds weight to the lathe base).
http://www.harborfreight.com/18-in-7-drawer-glossy-red-end-cabinet-for-roller-tool-chest-68785.html
If you mount the VFD in a separate NEMA cabinet like the one noted, I probably would mount it on the back of the splash shield if your lathe is not going against a wall. Otherwise, leave enough cable and mount to a wall. Just did a complete VFD build for another member, this is what we ended up doing, except he is mounting it on the splash shield back at the tail stock end instead of the headstock due to access reasons. I also mounted a 5C collet rack at the tail stock end on the lathe cabinet so I have quick access to the collets. You can also use a DIN steel rail for the the QCTP tool holders if you do not have a side cabinet to put them in. Also didn't like the light mounted at the headstock end, as it can interferes with the DRO when you reposition it (remounted mine more toward the center of the splash field). Lots of options....., have fun with your new lathes, you will really appreciate them in use. Look forward to your builds and comments.
Mark
