I'm waiting on a few parts from Joel and some monkey repellent from the publishers of the Satanic Bible.
I doubt I'll ever do the tapered roller bearing conversion unless I have to do a bunch of fine facing operations.
Believe me, it is possible to the point of certainty that you can set up a high frequency resonance in the axial plane of the spindle simply by banging the roller bearings back and forth. The noise is rich in harmonics which distinguishes it from ordinary high frequency tool chatter.
Meanwhile , back to the flying monkeys with hammers.
The list of damage
Someone pounded on the headstock end of the lead screw thinking that it came out of the support casting that direction. Seems reading the parts breakdown wasn't an option. That or monkeys can't read.
While pounding on the lead screw end the end was so severely peened over that removal of the spacer behind the spindle drive gear was impossible. This resulted in hours of careful file and stone to restore the spindle diameter so the spacer would go off and on. Of course the 1/4 - 20 threads were buggered and had to be chased.
Then the casting had been tweaked just enough so that when the attaching screws were tightened the lead screw bound up. No small wonder as the spindle bore was pointing back at the bed. Looking back at the bore the years of neglect had left the natural bearing surface black with baked on goo and smooge. This all had to be carefully removed while not taking so much that the spindle fit became a hotdog down a hallway.
When we last visited the 141-023 Coupler, Direct Drive, it was resting in its as molested by flying monkeys with hammers state.
I didn't get pics of the process because getting the sweaty hands in and out of gloves was just a mess. Okay , I'm lazy. It just means I'll have to type more.
This, like many of the Atlas parts is Zamak or a close relative.
At some point the chuck had been stuck to the spindle.
The spindle shows some damage but the coupler took the brunt of it.
Inside that counter bore is an external snap-ring.
As received I didn't have the clearance to get the snap-ring out of the groove because the coupler was so badly squished. The snap-ring came out in pieces.
The spindle end was badly swollen, possibly from hammer blows, and not allowing the coupler to slide free. It took hours of patient rubbing to get the necessary clearance.
Then a condensed version of creating a bit more clearance for the drive pulley and bushings.
An entire afternoon of "smoking" the shaft and dealing with the high spots while checking with a mic to make sure I didn't go drastically undersized.
Then removal of the spindle back gear. This was an all day sucker.
So back to the coupler. It was unusable as it was and they seem rare as rooster teeth.
Inspiration.
I closed down the jaws of the 3 jaw and placed the damaged end of the coupler over them.
Rotate, expand, retract, rotate, expand, retract, rotate, repeat....
Major gains were made.
4 jaw.
Trade out the three jaw for the 4 jaw and place a woodruff key on one of the jaws in an attempt to more or less nearly circularize the remaining damage.
Rotate, expand, retract, rotate, expand, retract, rotate, repeat....
I then had clearance around the entire shaft for circlip installation.
It's still ugly as sin but it engages and disengages.
The ball detent even survived.