jonesra, the Calypso looks to be similar to the Corsair which also uses a smaller spool than the bigger portables and standards. Do these spools seem to be similar to the ones you have?
https://www.ebay.com/itm/Smith-Corona-Typewriter-Ribbon-Corsair-DeLuxe-Cougar-Zephyr-Super-G-Skyriter-SCM/152632666844?hash=item23899daadc:g:2cUAAOSwl2RZciN6

Hi Jonesra

​Oliver is correct, your Calypso takes the Smith-Corona series 3 spools. These spools were used on the entire Y- series of the Smith Corona typewriters, right from the very first 1Y- Zephyrs through the Skyriter 2Y- to 4Y-, onto the 5Y- to 7Y- light portables like your machine and the Super-G and lastly on the portable electrics like the CT and XT series.

​Here's where letting us know your location in the first post really helps. This is an international forum base in Canada with a large US contingent of members. Therefore, it's not unreasonable for members to assume you are also in the USA. As we now know you are in the UK, I was going to suggest Globe Typewriters or Oliver typewriter supplies or The Typewriter Man in Luton, but none of those show any stock of SC series 3 ribbon spools. Therefore, it looks like Oliver's link is probably your best bet.

​Occasionally, I manage to find an older model Skyriter that still has one or both metal spools. These are becoming almost as rare as hen's teeth, so I'll wind fresh ribbon onto these and keep them with my Zephyr and early Skyriters. All the best,

​Sky

Hi Tom
I'm unable to send private messages yet as i haven't posted enough times, but yes I am interested in buying them, are you able to message me?
Rachel