30mm Adapter for 23mm Ultra Wide Microscope Eyepiece

This is an adapter which allows you to replace the 23mm shaft of a generic 23mm-shafted 10x/22 eyepiece with a 30mm shaft so it can be used in a 30mm ocular, where it gives a ~26mm ultrawide field of view. These work as a drop-in replacement for expensive Nikon CFUW/CFUWN ultra widefield eyepieces. I hope to update this design to incorporate a field stop to remove slight shading and distortion on the far periphery.
For more information see
http://www.microbehunter.com/microscopy-forum/viewtopic.php?f=14&t=10094
Have printed in both PLA and PETG, both seem to work fine.