UPDATES10/29/14 - Added the matching spool - thing: 52200510/7/14 - Added a combined STL7/6/14 - I've added a PDF Read Me guide to using the adapter6/16/14 - updated files to improve fit and reduce friction. May be loose on some commercial canisters but will now fit CineStill film and possibly Kalt. Print using 50% infill.Tested and working. This adapts 35mm film canisters to work as a 120 format spool, and allows shooting 35mm film in any 120 medium format film camera. The 35mm film is centered on the 120 spool. Using this adapter allows using films that are not available in 120 format, and the entire 35mm film is exposed, resulting in images out to the edges, sprocket holes and all, resulting in a unique effect.You may also want the matching spool at http://www.thingiverse.com/thing:522005Do not force adapters on. Make sure the splines are aligned and if tight, trim/sand or wiggle on carefully. The splines may need to be trimmed to fit Kalt bulk loading canisters and some others.The hole for viewing the film number (usually a red window) on the camera must be taped over with black gaffer's tape or some suitable opaque tape to avoid back side exposure of the film. You will need to wind blindly about 1-1/2 turns at the beginning and taper down to 1-1/4 turn at the end. Most medium format cameras have no rewind, so you will need to unload the film in a darkroom or changing bag and manually rewind the 35mm film back into its canister. When processing, specify "process only" and "do not cut" and cut the film yourself.These were designed for the Flyer 6x6 camera developed as a result of the Pinhole Printed Kickstarter project (pinholeprinted.com) but can be used in any 120 medium format camera.The combined STL is printed as is. If using the individual parts, the bottom STL part is printed as is and the top STL part must first be rotated 180 degrees about X or Y to sit flat on the bed for printing. Now recommending 50% infill due to the small cross-section of the splines.If you do not have a 3D printer or have it tied up with other things, check at http://www.pinholeprinted.com/order/35mm-film-to-120-spool-adapter/ for alternatives.This is CC by SA 3.0 - this means anyone can freely print or even sell the adapters - but you must provide attribution if you do so. You can print a Thing Tag right off this page and display it if demonstrating your printer capabilities or distribute it with any copies you sell.