reply to u/Ill_Tear8308

Not so much that they're proprietary, but the Zephyr, Skyriter, and later Corsairs used the 1 5/8" diameter spools, which fit about 12 yards of ribbon versus the more common universal 2" spools which will hold 16 yards of ribbon.

1/2" wide ribbon should work on this. Sellers include: https://site.xavier.edu/polt/typewriters/tw-faq.html#q1

If you wind it onto pre-existing spools keep in mind that Smith-Coronas typically used eyelets in the ribbon to effect the auto-ribbon reverse, though you could certainly do it manually if you needed to.

There aren't a lot of examples of Empire-Coronas in the typewriter database, so be sure to include your example with photos:

https://typewriterdatabase.com/empire.24.typewriter-serial-number-database

https://typewriterdatabase.com/Empire.-Corona+Skyriter.24.bmys

reply to u/actualwoey at https://old.reddit.com/r/typewriters/comments/1gqhied/recommendations_for_reliable_new_small_spool_1_58/

You could see if a local repair shop is parting out a machine or has spools that would work for you. iirc the Corona Zephyr, Skyriter, and the later versions of the Corsair all used that smaller spool size, usually described as 1 5/8" or 1 2/3". https://site.xavier.edu/polt/typewriters/tw-repair.html Once you've got the correct sized spools, you can wind your Amazon ribbon onto them, but you'll likely have to trim it down to fit. (2" spools usually have 16 yards of ribbon while the 1 5/8" accommodate about 12 yards.)

If you can't come up with original metal spools to respool your 1/2" ribbon onto, you can try https://www.ribbonsunlimited.com/category-s/12779.htm which will sell you both in one go.

Some other ribbon options: https://site.xavier.edu/polt/typewriters/tw-faq.html#q1. I've had good luck buying bulk ribbon from both Baco Ribbon and Fine Line.

I've heard some have successfully re-juvenated old ribbon by spraying it (unspooled into a box) with WD-40 or glycerine to re-wet it and then respooling it.

A list of typewriters that have general exceptions to the broad categories of typewriter spools. One will want to keep and use the original metal spools for these.