I'm in agreement with John, Work harder is a bit mean though..
If well insulated the likes of a small oil radiator would be more controllable and keep the chill off, some mention the greenhouse heater tube used under the bench/lathe, again need to keep shavings clear.
I'd consider you'd not keep a burner stock with your small volume work. I'd Turned for a commercial firm who had such a stove, a days worth of waste, even more than knee deep gave an hour or two.
Cheers David