Here's an electrical solution that I just tested. I think it solves
  the problem effectively and safely. Total cost about $2.50. Total time
  30-60 mins depending on your skill level.

  You will need:

  (1) a new DPDT switch, Radio Shack part # 275-1533 (part number may be
      out of date, I'm looking at a 1996 catalog)

  (2) a short piece of wire (3-4 inches) about 20 gauge. (diameter of
      conductor should be no smaller than the existing wires on the F/R
      switch).

  (3) a low wattage (25-50 W) soldering iron and solder

  (4) rudimentary soldering skills

  * Unplug the lathe power cord

  * Remove the power supply box from the lathe (4 screws) and flip it
    over (same as for low-speed mod)

  * Two wires run from a black plastic terminal block to the bottom two
    terminals of the F/R switch. On my machine the wires are labeled 1 and
    2. 

  * Unsolder wire 2 from the bottom left terminal of the F/R switch and
    solder it to the center terminal on either side of the new switch (you
    will be using the terminals on only one side of the new switch)

  * Unsolder the (blue, on my lathe) wire from the top right terminal of
    the F/R switch and solder it to either terminal on the same side of the
    new switch as the wire from the previous step.

  * Solder a new wire from to top right terminal of the F/R switch to the
    other terminal on the same side of the new switch.

  * Check all solder connections to make sure they are bright and shiny
    and that you have no shorts between terminals. Be sure, since a short 
    will blow out the power supply and/or motor!

  * Drill a 1/2 hole on the left side of the power supply box and mount
    the new switch.

  * Plug the lathe back in and turn it on.

      Now both the F/R switch and the new switch must be in synch to change
  direction. If you are in Forward and switch to Reverse, the motor will
  not start until the new switch is in the Reverse position as well. 
  Same thing going from Reverse to Forward.