Here is the simplest method around for making adapters so that you can fit modern, plastic-spooled 120 film into most 116 cameras! (or the narrow 616 type, if you trim the flanges)

1. Raw material: 1/4-20 Round Combo Screws




2. Ream out to .25" deep with 5/32" drill




3. Cut down to .25" remaining thread




4. Bevel the cut edge with mill bastard file edge




5. Screw into empty 120 holder and take off excess height...




6. Until the ends are even and match original width




7. Test it out!




Enjoy!

Caveats:

1. These adapters are meant to adapt the 120 spool into the pins of camera holders of the type that have a pin at each end. The front-loading Pocket Kodak 2A cameras, for example, depended on the width of the original flange to keep the spool in place, hence these adapters won't work for those models.
2. The 120 plastic flange fits into the wider 116 chambers easily. To fit the narrower 616 chambers, this flange needs trimmed. Use toenail clippers to clip off the outer raised edge of the 120 spool ends.
3. These adapters happened to fit one particular cross-cut 120 spool end that I tested with, but it is possible that the 1/4" thread may be too large or too small for others. YMMV.

There may be more.