I redid this from scratch based on an original Canon lense-cap. It has more details that the simpler copies from other lense manufacturers not have. It is also tapered to stay fixed in the lense.Status: I DID NOT PRINT THIS YET! I hope to print this next weekend.Done in Alibre Design. (there is a 30 day trial that can handle this thing)Make a lense-cap: 1: print 2: attach a plate to the upper end. (not part of the design because the overhang would be nearly unprintable.)