I used fabric glue, but if you want to sew them on, I don't see why you couldn't! Just try to pick either a transparent thread or a thread with a color that matches the color of your gears well so that it won't stand out.
Super easy to do, make one! Less-than-high-quality Hot Topic fedora, package of Tim Holtz gears (check the scrapbooking section of your local craft store, ask for it by name) and a random decorative key.
i recently bought a black top hat and want to steampunk it and i was wondering what you used to secure the cogs onto the hat?
Also, thanks!
This is incredible. Have you tried doing this with one of those bowl-shaped twenties-style hats? I wish I knew what they were called.