HF 8x12 quick reverse

[Ed Boysun]

As I mentioned previously, the shallow threads on the first lead-screw idler quickly stripped out of the cast headstock. I turned a new spindle for the gear that had much longer threads and would be more resistant to stripping. Because I lacked a way to make a hex head I left a sizeable round collar between the gear and the headstock. Further thought convinced me that this round collar could serve as a swivel point for a much quicker way to reverse directions for the leadscrew. Pic 001 shows the long threaded spindle and the first stages of a roughed out bracket to hold the spindle for a reverse idler. The new spindle for the reverse idler is also shown. Threaded part is 3/8" NF threads. The threaded part was turned to be eccentric to the gear shaft by shimming one jaw of the 3-jaw chuck with a piece of .015 steel. The eccentric was to allow fine tuning the gear spacing on the new bracket.
Pic 002 shows the finished pieces, ready for assembly. The bracket has been drilled and tapped for set screws. One to lock the eccentric axle when proper gear lash has been obtained. The second one is to be used for tightening the primary axle into the headstock. It is removed once the spindle is tight. A short piece of socket has been cut to fit over the nut and serve as a pivot point for the strap that serves as the actuating arm.
Pic 003 and 004 show the pieces assembled and nested together, ready to be mounted to the headstock.
Pic 005 shows the new gear assembly in the reverse position.
Pic 006 is the gear in forward position. Of course the change-gear banjo needs to be mounted and swung to engage the proper idler gear but it has been left off for the picture.
Ed B