I want to make a copy of my apartment key, which is all steel and decent weight. The three locksmiths in my area all use the cheap lightweight blanks with plastic black knob. These copies don't work well in my lock.

Anyone know of a more professional locksmith or keymaker?

It is usually a bit crappy with a new key, unfortunately. A trick I use is to put a bit of oil (not WD40) in the lock. Everything works better, and with a little use the keys will fit better too. You could also take off all of the corners on the teeth of the keys with a bit of abrasive paper.

Thanks tigertiger. All good suggestions. It's just a backup/guest key, but the three tries so far have been so unwieldy, not sure they are worth trying to save. I'll probably just keep looking (in vain) for some shop that actually carries a full metal blank.

Putting oil in locks will make them get stuck in the future. The oil will degrade and absorb all kind of impurities that can cause the lock to malfunction even worse than before.
It is thus only a short time solution and should not be used if you intend to use the lock much longer.
The right lubricant to use is graphite powder. One puff in the lock is usually enough.
You will recognise a professional locksmith by the use of this. Oil = not professional, Graphite = professional.

WD40 is not a long term lubricant but can get locks that are stuck because of old oil moving again.

Probably better to change the whole cylinder (The part of the lock that accepts the key) and get a full set of keys with it.

Cool, didn't know about the graphite powder.