paul, that's +/- correct.
it comes down to 1 big thing legally, and another in terms of being excellent.
legally: we can't provide service to a business at a discount that would in effect be us supporting them. so on the cutter, if it were going to consume a lot of electricity, (which it's not, but a plasma cutter or mill might) then we'd need to be able to document that we're billing for it to protect our status, and adam from audit fiasco. a nominal fee for it's use is us compensating him for wear and tear on it, and ~includes some rental fee for the few sq feet offset by the awesomeness of it being there, and electricity use.
excellently: making a profit in the space is cool as long as you are respectful of everyone else. i.e. using materials donated to the community for the majority of your stuff is you personally in effect selling community supplies for your own profit- not cool. were you to say donate back appropriate amounts (say +/- what retail would have been for the wood/scanner parts/gas, etc) then you're contributing back to the community, but that wouldn't be tax deductible and we'd prolly have to report sales tax on it. likewise, if you're monopolizing a tool, or space, or causing undue wear on something like a saw blade or abrasive wheel, you are using something up that 70 other members "own" for your own profit.
it comes back to the copier at work scenario. if you're gonna print off a few sheets, no biggie, if you're gonna print out war and peace, that's fine if you do it at non-peak hours and bring in your own paper, but if you're gonna start binding pamphlets and selling them, you should buy your own copier/printer.