what is the procedure to operate the quill manually ?
The procedure involves flipping a toggle switch. No need in removing the bolts. Obviously, its a bit more stiff because your having to turn the screw and the motor too, but it is definitely doable. I would hate to think that I had to tear into the thing every time I tripped the limit switch and disassemble the mechanism to move off the switch. If I had a nickle for every time I tripped the limit, well.......I'd have enough for about 2 gallons of gasoline. 1 gallon if there's a mild hurricane in the gulf (Grrrrrrrrrr!!!!!! try to stay on topic, Sam!) Personally, I hate the system and always thought "there's gotta be a better way". The single bolt that goes through the spindle is the bread and butter of the whole deal. It was never designed to take cutting forces and drive the spindle. Ours gets loose from time to time, so I keep an eye on it. Having to maneuver an allen wrench sideways between the ball screw and the enclosure and apply any effective tightening pressures without snapping the ball on the wrench definitely contributed to the "better way" theory. On Hoods system, it looks easy enough to slap a boxed-end wrench on it and really get mean with it. All of our work is 2.5 axis stuff. I would not want this system if I were doing 3 axis jobs. I just don't think the single 1/4-28 "bread and butter" bolt would survive through the long haul of repetitive up/down motion. Maybe Hood, Beachbum, or somebody else can give there $.02 cents on that. Now if your not skeered to tear into the spindle and punch a couple larger holes through it, it would definitely beef things up a bit.