This is exactly what i mean.I THINK the original poster was wanting a device to sut the tounge to attach to the spool inside the cassette. These days we have to use DX coded reusable cassettes, to get our High tech film camera to know what film they are shooting. ALl the cassettes I have purchased recently come with a spool designed for the film loading machines used by the film factories. they expact the film to be tapered and have either 1 or two small holes to catch on a hook moulded into the cassette. They are the same as most makers (except Kodak) use for film.
As a work around I have been tossing the spools that come with them, and instead using spools salvaged from Kodak Film. This requires a bit of manipulation of masking tape in the dark.
IF there was a small device like a paper punch, that one could stick the end of the film in, and squeze, replicating the outline of the tail end of the factory film, one could just stuff the film into the spool, and be done. The result would then be identical to what comes from the factory.
The tongue outside the cassette is not as hard to do, and is dependent on the camera(s) in use. And it also can of course be cut in the light.
I would be willing to pay say 30 bucks US for such a device.