When does an owner cross the line from being an enabler of the contributor class and becomes an exploiter of the contributor class?

Say I am a machinist and I save enough to buy my own machine. I bring on a apprentice and teach them to run the machine and I focus more on finding customers and maintaining the machine and finding another apprentice. Maybe I buy a second machine. How big can this grow before I am no longer enabling these apprentices and I start exploiting them. Am I making a profit or just earning my money. I could structure the business so that I made a wage just like the workers but is my fair wage only what they make or can I pay myself more?

TEK