Black Slaveowners
Free Black Slave Masters in South Carolina, 1790-1860
by Larry Koger; 1985
ISBN 0-89950-160-5

From the forward:

"In South carolina, free Negro masters were similar to white slaveowners. Both exploited the labor of slaves with the desire for profits. Quite often, the colored artisans bought slaves to be hired out and then kept the wages of their bondsmen. They also established a master-slave relationship which demanded subservience from their slaves...."

Try to get this book, period.

Peace
"Guided by the Ancestors"