If you are disturbing other tenants, most landlords will find a way to remove you. There are lots of reasons available in most states if the landlord wants to document things. I have tenants who pay me on time, don't flood their bathroom, replace their own light bulbs, and plunge their own toilets. Most are well past their one year lease and have no intention of moving. If I start getting calls from them about the new guy who is running a machine shop in his spare bedroom, that is going to get my attention.
I would only purchase a mill if it had R8 spindle. There is an incredible amount of R8 tooling on the secondary market at great prices.
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My current work-space is a little damp, but I'm planning to purchase another building with a dry area to set one of these up.
More expensive, but I'm a whole lot better at writing a program than holding consistent speed turning the wheels. If you price small jobs to where you are paying your overhead, tooling, and some scrap, and count your time as experience, I don't think you will have trouble finding small jobs not requiring an FFL that will go a long way towards paying for a small work space and decent machines. Especially if you are near a farm community.
If you get a bigger machine, make sure you have a plan to transport it. If you have to pay someone to deliver that may cost almost as much as the machine itself.
Here is a good test for you. Figure out what depth of cuts you can take with the various machines you are interested in on the materials you will be working with, then go into your lab and try to d one of your school projects limiting yourself to those depth of cuts, tool diameters, etc. See how long until you are pulling your hair out. I've worked on some 60HP CNC machines. Machines you could stand inside without looking ridiculous. Machines that can take off a half inch at a time without knowing it. Trying to do even small work .050 or less a pass would frustrate me quickly.