The spindle in the engraver had about 1/8" of axial play. Here's a short post on the teardown and how it was fixed.
This picture shows the components:
1. Lock the head. Then remove the bit, collet, and inner shaft. 2. Then using a needle nose pliers remove the base completely. 3. Next remove the lock washer using a snap ring pliers. 4. Remove the spacer and then the nut that locks the shaft in place. 5. Unlock the head. Then push the whole motor shaft out. Once the nut is removed it is held in place by the magnets.
The problem was the outer race of the bearings was not held in place by the retaining spacer and lock washer. It bottomed out before tightening against the outer race of the bearing.
To fix it just I just made a spacer from a washer and now it locks properly without any play.
Hope it helps someone!