How do you attach a gear to a bolt or a spindle?

specific gears are hard to find, if you build it in truespace beta, you could build the spindle for the gear with a flat round purchased from ebay by holding it steady and working the teath with the small carbon grinder on a drill press. First you have to attach it with a bearing, you just do a google product search for the size bearing that you found it to be in truespace, usually from an 82 volve, but ALOT cheaper.