Saw your reply to Davina and thought you might want to look at Foil Stamp Solutions.
We manufacture several foil machines for many different applications.
The One Air operated machine has been the most popular machine with Letter Press people. It is a table top unit with the power of a large press. It provides clean , crisp and professional results and is inexpensive compared to windmill add on components.
Check out the website foilstampsolutions.com and give us a call.
I use a KINGSLEY HOTFOIL MACHINE. there are always examples for sale on eBay. If you’re still looking, check out the Kingsley. Stick with model M-60 or above, so that you have a two-line machine and therefore more versatile. you only really need the pneumatic function if you are doing hundreds of imprints at a time. also, check out the page https://www.facebook.com/KingsleyMachineCo/ for good reference info and images.