Thank you all for your help. I gather I have 3 options; 1) contact Smithy and get a replacement, 2) buy a close match and machine it to fit, 3) make your own.
I researched close matches and am having problems finding the 63 tooth gear, its not a standard or common size. I reached out to Smithy but have not received any replies, so I will try to make my own.
EDIT: Smithy responded to my query, they sell the gears and are very reasonably priced. Although its more cost effective to buy the 2 broken gears I still want to make the gears myself.
The challenges I need to overcome are; cutting the gears and making the bore.
I have been wanting to cut gears and now I have an opportunity to both replace broken parts and expand my lathes capabilities. My lathe can cut 11-40 tpi threads. By adding 24, 80 & 90 tooth gears I can cut 6-10 tpi threads. I searched for module 1 gear cutters. The standard cutters have size ranges so I would need to purchase two or three cutters to make the sizes I need and they are somewhat expensive. I researched making a gear cutter and I had success in finding an inexpensive way of making a cutter for all the sizes I need.
As to the bore, I needed a bushing for the broach that had a keyway cut at 90 deg to the broach.
I made the bushing from some scrap, turned to 15mm diameter with a 19mm flange. Used the spin indexer and milled 2 groves at 90 deg, one for the broach and the other to index the keyway.
I found a website
http://www.helicron.net/workshop/gearcutting/ that described a hybrid cutter. I followed the instructions and made a prototype cutter from scrap 5/8" steel rod and I cut a gear out of an aluminum sprue to validate the process. The resulting gear meshed well, I am very happy with the cutter and gear.
Now that I know I can do it I will create a members project and show the process. The replacement gears will be made of steel, the cutter will be made from tool steel and hardened.
Thanks again,
Caster