I have a small machine shop where I make little doodads out of metal. All of my equipment is manual. If I want to cut metal on my lathe or mill, I'm spinning handwheels and engaging power feed levers. I then have to sit there, watch the beautiful blue steel chips fly, listen to the sound of the cut, and wait for the cut to be finished so I can turn off the power feed. Then I turn off the machine, get out my micrometers, carefully measure my cut, and do it again until I'm done. Then, I take the work out of the vise or chuck, grab my file, debur all of the sharp edges (I love the sound of a good file knocking off metal burrs), and get to work on the next part.

It's intensely peaceful. Machining tools are relatively quiet and stately (power woodworking tools scream like evil demons). Small hobby tools are slow, so you always have plenty of time to enjoy yourself. It requires a lot of planning and thinking, and it helps you develop a much more attuned mechanical touch. You get to make really cool shit out of the best material (i.e. metal), and it's a genuinely useful skill. I do software development, and I spend way too much time sitting at my desk. Machining is my escape.

One downside is that it can be expensive. Good tools cost money and good metal costs money. I'd guess that I have $20K invested in my shop, but I've also been doing this for 7 years now. The initial investment isn't that high. You can save a lot of money by making your own tools, which I didn't always do. Used tools are also a really great option (except for measuring tools, sometimes you have to buy those new). To get metal for cheaper, go to nearby machine shops and ask nicely if you can buy scraps from their offcut sections. If you tell them that you're learning machining, they'll be very likely to oblige!

The other downside is that it requires you to be careful. Human flesh is soft compared to metal. Machining is only dangerous if you're incautious, but I feel like it's important that I bring up safety when I recommend machining as a potential hobby.

If you're interested, check out Blondihacks on YouTube. She has some great videos on how to get started with your own hobby machine shop. I also really like Clickspring and This Old Tony. Clickspring has some good project videos on his channel, and TOT is hilarious and educational.

Here's the thing I'm most proud of making. I adapted the design of a 3D printed yarn winder to manual machining and built it from scratch. All of the metal parts started out as raw stock (everything is 4340 steel, except for the base plate which is ductile iron). The base is black walnut. The little feet are brass, with sorbothane feet on the bottom.