The file has been updated based on feedback from a user and fit has been verified. You *must* check first that a 35mm film canister will fit into the 620 recess and that you can close the camera door - if you can do this, the adapter will most likely work.
Do you have an old 620 film camera? Want to shoot images with the sprocket holes exposed? Want to shoot specialty films that are not available in 620 format? If so, or you just like to play with film, this adapter may be for you.
THIS IS IN BETA STAGE - meaning, this is based on the working 120 adapter, and it is dimensionally accurate on the end slots, diameter, and length for 620, and it should work but has not been tested in practice since I don't have a 620 camera. Please check that a 35mm film canister will physically fit and you can close the back, as 620 spools are 22.5mm in diameter and 120 spools (and 35mm film canisters) are 25mm in diameter, so this might not fit in some 620 cameras.
This adapts 35mm film canisters to work as a 620 format spool, and allows shooting 35mm film in some old 620 medium format film cameras. The 35mm film is centered on the 620 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.
Do 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. For 6x6 format, 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.
The 120 adapters (Shapeways #2733750) were designed for the Flyer 6x6 camera developed as a result of the Pinhole Printed Kickstarter project (pinholeprinted.com) and have been modified for use in 620 cameras (not usable in 120 cameras).
License: CC by SA 3.0 - Attribution required