I recently picked up an old 620 film camera and wanted to make pictures with it. It came with a 620 take-up spool so all I needed to do was adapt 120 rolls to fit. I began by checking the 'net for ways and means. Oh, boy! It appeared as if my choices left me somewhere between the re-rolling rock and the sand-down-the-edges hard place. [All that work or dust! And still stuck with the end hole/slot difference.] So what to do? The first problem tackled was the diameter of the 120 film spool ends. A heavy-duty nail clipper [toenail clipper] with a curved cut allowed me to trim the spool end diameters down quickly and efficiently. About a minute/roll, taking time out to sip some sherry. That left the slots. In a few minutes, using white printer paper [24 weght] and a drill bit for a mandril, I coated some 3/8" wide strips of paper with glue and rolled them to form tubes. The ID was that of the central hole in a 620 spool. The OD was the same as the central hole in a 120 film spool. Put them in the end holes of the 120 spool and it became a 620 spool. In simple words: take a 120 roll, trim the edges with toenail clippers, put in 3/8" long glued paper cylinders to reduce the hole size, load and shoot. That's all, folks!