The above github link contains a CAD file meant to be sent to a service like SendCutSend, or a local machine shop. The resulting parts need only have bolts, nuts and washers added to complete assembly.
The public domain Any Holder Camera Film Scanner is a platform to enable scanning film/slides up to medium format, with a digital camera using any (most) film holders/carriers.
Unlike most current solutions that are geared toward scanning intact rolls of film, the Any Holder Camera Film Scanner is designed for scanning film strips and multiple slides at a time.
Minimum requirements are a 8"x10" or smaller quality light source for backlighting the film, a digital camera, and a film/slide holder no wider than 4.5". It is sized to be placed on a copystand, which is the best practice for quality, repeatable scanning.