Had a great time cleaning and repairing this 21J Lord Elgin!
Had some trouble with the spring barrel, where the spring would pop off of the barrel arbor. After talking to a local watch repair shop i learned a trick where you bend-out the end tab on the main spring slightly so it pushes itself towards the barrel arbor when the watch is wound. In addition to this, you can scratch the key on the barrel arbor that would normally hold the end of the main spring, where the key meets the arbor.
These tricks worked and now this is one of my best vintage wrist watches.