Suggestions to other thumb-fingered 'gunsmiths' like me:
Don't drop the frame while in the middle of disassembly. Parts fall out and hide - look under the table. A magnet will help.
As Bullseye suggests, try not to let the hammer pivot pin come all the way out. The thumb safety is also on the pivot pin and holds the sear and spring in place. If it comes out, you will learn much more about the internal workings of the 22/45 than you intended. See also above RE: dropping the frame during disassembly.

The pin that holds the sear is easy to dislodge while trying to catch the frame on the way to the floor. Make sure it is connected to both sides before reassembly.
Again, Bullseye's instructions saved the day.
