I made a 1015 assembly jig by making a slot in the end of some scrap wood and driving in a headless brad at the right place to hold the coupler box.
Drop the bottom of the box over the brad, put the two pieces into the box over the brad with the "hose" in the slot, pop in the spring in on the end of a jeweler's screwdriver, snap on the lid.
I've been using it since we had to join the box with a soldering iron...