How do you lock a bi-fold door so a 2 year old cant get in? You search the thingiverse and print what you find. Duh!!
This is what I found: http://www.thingiverse.com/thing:263534 it was close but not quite right. The width for the door was too big. No worries I can re-spin it for my doors an 5 mins of work.
This is what I did: