This mini ornament hanger is designed to hold a 1.4 inch long ornament with a 7mm (millimeter) diameter internal hole along this axis. You can make your own ornaments using various materials, beads, or purchase compatible ornaments in this store.
The bottom cap is connected to the main hanger with a small sprue that you need to cut off. Connecting the two parts in this way reduces the cost by eliminating multiple parts handling charges at Shapeways. Cut the sprue with a pair of small wire cutters or a strong pair of scissors where the screw thread ends. You may need to sand this end smooth a little for a proper fit.
It is likely that residual powder from fabrication will be present within the screw threads of the bottom cap and you won't be able to screw the parts together until this powder is removed. An easy way to remove this powder is to slowly screw and unscrew the two parts together in a bowl of water or under a low stream of water from a faucet, rinsing out the cap between attempts as the powder is loosened. It only takes about a minute to do this and once the residual powder is gone the cap should screw flush with the main body of the hanger.
If you want a permanent assembly you can use a small dab of glue on the screw threads to keep the cap in place on the hanger body. Once assembled there will be a small hole present in the end of the cap at the bottom of the assembled ornament. In general this will not be noticed after the ornament is hung. However, if you want to try and fill the hole you will notice that there is a very small disk and the far end of the sprue. If you carefully cut this small disk from the sprue you may be able to press fit it (or glue it) into the hole. Alternately you could fill this hole with glue or epoxy if you prefer.