Steve,
I think I've come up with the ultimate speed control.  I haven't seen anything else like it so I wanted to share it with you.  I've had this project in the works since I last talked with you a couple of years ago.  Since then I moved and all projects were set on the back burner.  I finally have gotten my shop up and running and have been able to start getting some things done.  Among these was to finish the DC conversion of my 9x20, inspired by your work.  I started watching for a controller and motor on Ebay.  I ended up with a KB Electronics KBCC-125 bundled with a 1.5hp treadmill motor for something like $60.  I wasn't very impressed with the motor.  I'm assuming the 1.5hp rating was instantaneous peak HP with the armature locked and not actually sustainable.  I would think it's actual rating is probably closer to 1/2 horse continuous, but probably adequate for the 9x20.  The real gem in the package was the KB speed controller.  It was very well built and flexible, although it didn't support plug reversing or braking.  When reading the manual, I did notice that a -R version was available which supported both reversing and braking.  Wish I had known, I'd have picked one of them up instead.  Well as things worked out. I ended up using this setup on my Bridgeport M-head mill that I finally brought home from work.  It was 3 phase but I didn't have it at home.  So instead of getting a phase converter, I ended up converting it to DC with the treadmill motor and KB controller. A few months later, I ran across a really nice 2hp 90vdc Baldor Industrial motor on Fleabay that I stole for $25 + $25 shipping. It was Identical to this one but without the mounting base.
 
 

Shortly thereafter, I came across a KBCC-125-R controller.  I didn't get. this one so cheap, I think I paid $100 for it
 
 

It's rated for 1.5hp max, but I didn't really expect that to be much of an issue with the 9x20.  One of the great features of this controller, besides the ability to plug reverse, was it had accomodations for a jog circuit.  I realize that a lot of controllers have a jog function, but the KB implementation is special (I think?).  After studying the various control configurations offered in the KB manual, I figured out a way to design a jog circuit with completely independent speed and direction controls.  This is what I came up with:
 

Now that I had the perfect motor and the ideal speed controller, the last element I needed was a tach.  I was going to purchase the same tach that you did.  But by chance I happened to run across a KB speed controller on Fleabay that had a built in tach that could also display surface feet / minute.  With a bit of research I found out that the tach was called the Tachulator and was actually an independent product that had been incorporated into the speed controller.

I went to www.mkctools.com/tachulator.htm where I was able to purchase the bare Tachulator board without a case for just a little bit more than the tach from the Little Machine Shop.  It has a resolution of 1 rpm, and can read as slow as 3 rpm's if a 16 pitch target is used.  If a simple single pitch target is used, it's minimum reading is 50 rpm.  It uses an IR transmitter/receiver in a reflective mode rather than the interrupted mode of the LMS tach so a different approach was needed.  The tach manual comes with a couple of targets that you can use.  They are simple black & white radial targets, like a pie, designed to be glued on the end of a shaft.  Because the drive pulley isn't flat, there was just no good place to stick one of these targets.  I was also concerned that over time oil and crud would end up being flung on it interferring with the readings.  I found the perfect solution was to create a new target consisting of alternating black and white bands that could be wrapped around the spindle shaft and taped inside the 'headstock' between the bearings where it would be shielded from oil, dirt, and debris.  It also keeps it out of direct light which could interfere with it's reading.  A simple sheet aluminum bracket was good enough to support the sensor.
I produced the target using Autocad, having measured the diameter of the spindle then calculating the circumference to get the length correct.I wanted to use the original lower pulley assy. off the stock motor to retain the ability to change belt ratios.  Unfortunately, the shaft on the Baldor motor is larger than the stock motor.  Because I wanted to be able to put the stock drive back in at any time, I didn't want to bore out the original pulley.  So once again, I derived inspiration from your work and hacked out a new gear just to drive the xl belt.

I don't remember what went wrong with the first attempt.  I think maybe I cut the teeth a touch too deep which screwed up the profile.  In any event, the second time worked out and I ended up with this.
 
 

This is only a temporary solution.  Eventually I want to order an original replacement pulley to bore and fit it to my motor for the other 3 ratios.  But for now, this is working fine:
 

I mounted the speed controller inside the cabinet to keep it free from oil and swarf:
 

The relay attached by the terminal block switches the main power, which is remotely controlled via the operating panel:
 
 

The Run/Jog switch is a DPDT center off with an extended handle.  It was originally momentary in both directions, but I was able to disassemble the switch and remove one of the return springs so it stays in the run position but retains the momentary action for Jog.  The power switch is an Allen Bradley push button switch with a 24 volt indicator bulb.  I used two 2.2k / 5watt resistors in series to get 4.4k to drop the 120vac down enough to power the bulb without a transformer.  The box is a project box I picked up at Radio Scrap along with the 2 speed control knobs.  I made both the bezel and the knob for the Tachulator.  The lettering is all done with dry transfer sheets.  To protect it I overlayed the entire panel with a piece of mylar sheet I had in stock.  The 2 aluminum strips down the sides hold down and protect the edges of the mylar sheet.My current speed range is about 12 rpm on the low side using the lowest speed pulley, and around 1600 rpm on the high side using the highest speed pulley using relatively conservative settings on the speed controller.  Once I replace the gear on the motor with an original pulley, the top speed will be significantly higher, exceeding the stock 2000 rpm, though I wouldn't operate it at those speeds for any length of time due to the greased spindle bearings.  With the standard 3 jaw chuck, the dynamic brake stops the chuck in about 2 seconds.  It is perfectly acceptable to switch to reverse at any time.  It will apply the brake and stop the spindle before it reverses direction.  This setup is perfect for cutting metric threads when you can't open the half-nut.  I have the Run speed set really slow forward for cutting the threads, and Jog set for reverse at high speed.  At the end of the cut I can back out the compound and hit Jog to quickly reverse back to the beginning, then start my next pass at the same dead slow speed every time.  Of course It is critical that any chuck used has a very positive lock on the spindle to avoid having the chuck spun off under the heavy braking or acceleration this controller can provde. This is probably the last of the modifications I'll be making to this lathe.  I'm going to pick up a Monarch 10ee in the next few weeks to take it's place.  It's just too limited in size and rigidity for a lot of the work I have.  I'll still keep the 9x20 around, mainly to be able to cut metric threads.I see that you are a gun enthusist.  Here's my latest project:
 
 

Took it to the range the other day and ran about a hundred rounds through it without a hitch.  The shells all looked good with no signs of deformity, head seperation, cracking or unseated primers.  Having passed the test fire stage, it's on to the final cleanup and finish work.  This thing is a blast, but a bit expensive to feed! Once again, thanks for all the great info and inspiration you've provided.  If it weren't for your site, there's a good chance I would never have done this conversion.  As always, feel free to post any of these pictures or text you'd like on your website to share with all the other 9x20 owners.  If you have any questions or answers, feel free to drop me a e-mail.All the best,   Marc Micllef