my monday evening included more progress on the 143b since its last mention on page 3839.
My goal was to get the bottom surface machined to be compatible with a newer style ri swivel base i picked up off of ebay. This required machining the bottom flat, taking the center locator down to 1.375" diameter and then finally squaring up the end of the locator. Squaring up the end of the locator is so i can bolt down a stepped retainer ring that will keep the swivel base attached to the main body of the vise even when there aren't swivel-lock-down bolts installed. I will share more of this process later.
As you can see in the pictures i was using pretty much all of the z-axis height that the machine has and the entire usable diameter of the rotary table. My stand-offs were hanging off the edge of the rotary table on each side. Having just enough clearance is what makes projects like this just a little more fun.
The end of the locator wasn't without a small challenge. In order to get the end of the locator machined i had to remove the 3/4-10 bolt that had been holding everything in place and rely on my trusty jack screws to apply the clamping force, they worked surprisingly well.
I thought i was done at this point but the 37/64" diameter mounting holes that a previous owner drilled into the main body were really bugging me. The holes weren't centered whatsoever and one of the locations was going to give me compatibility issues with the swivel base. I considered punching the holes out oversized to remove any evidence of the two poorly located holes and then use an insert in the base. However that was going to require a 1 inch diameter hole for 100% cleanup on two equally spaced holes and it would be getting into the vertical side wall of the vise more than i liked. This would have further weakened an area of the base that was never designed to be a mounting location in the first place. To maintain as much strength as possible i opted to just plunge a 5/8" diameter endmill through the base in two equally spaced locations that will be ideal for the swivel base circle opening. As you can see in the pictures these two new holes partially intersected the existing holes. The washers that i plan to use will cover of this oddly shaped hole. If this oddly shaped hole gives me issues i think i have a work-around.
Next up is deciding how important it is for me to make the swivel-locks tool-less with a traditional built-in handle or just use two 5/8-11 shcs and a 1/2" allen wrench for tightening and loosening. Of course the latter would be an easier and faster solution.

i also kind of like the idea of a self-contained adjustable handle clamp but i am too frugal to buy a set, perhaps i can make some instead?