What's a clever way to ask for a raise without threatening to quit - again?

I do damn good work at my job and I know – not think – that I deserve a raise. To get one before, I had to threaten to quit. Which worked because no one else would be stupid enough to do my job for such an insulting salary and there is no way a single mother like me can survive on my salary alone during this recession. Thank goodness I have other income, but that’s besides the point. I do most of the payroll and billing, so I know me getting a raise wouldn’t bankrupt the company. So how do I ask, without putting my position at jeopardy?