It’s already been discussed here how amazing the gear generator plugins are for fusion, so there isn’t much more I can add on that front… but what I can say is this… there aren’t many people out there who COULD manually draw a gear or socket (with the proper geometry) without having to scrap 4 or 5 different versions along the way.
The math alone involved in getting the perfect pitch and involute so that the contact area of each tooth isn’t binding or rubbing, or has too much slop etc.
Every scratch designed gear I’ve ever see made has involved hand drawing a scaled up version of a single tooth using protractors and a ton of trigonometry.
Those plug in’s do the insane amount of math for you, on demand, and they are able to generate the perfect gear profile for your application in no time flat!
If a generic profile is what you’re after, downloading the step file from McMaster MAY work, it’ll still be an approximation (depending on how the file was output and re-rendered on your machine) but for a low precision application, it should work just fine! If you’re looking to make a gear for a high-speed application, or for use inside of transmission or something, then you’ll almost certainly have to machine one from a billet on a mill, or hob one using a gear hobbing machine.