This is about the simplest way to make an accurate gear with the minimum of equipment, just a milling machine and a rotary table, no special attachments, no hobs or special cutters. And best of all you can use this method for any gear, even obscure sizes you can't get cutters for.
You can download the spreadsheet for free from my Patreon page (no Patreon account or donation required): https://www.patreon.com/posts/61153468