who was the first black slave to help cyrus mckormick with the reaper invention?

Answer 1

Don't know if he was a slave or not, but the name was Jo Anderson. He easily could have been a slave, as the McCormicks owned as many as nine slaves during Cyrus' lifetime. At the first link cited below, they call him McCormick's "trusted ***** helper."

The second link, Copyright ©2007 Prince William Network/Virginia Department of Education, writes, "Jo Anderson (a slave) and Cyrus McCormick worked to invent the reaper. The reaper increased the productivity of the American farmer."

However, the link for their citation is the same one I have as the first link below, which merely calls him a ***** helper.

See the first link to the biography from Shenandoah Valley Agricultural Research & Extension Center of the Virginia Agricultural Experiment Station (VAES)below.

Answer 2

Lucius Crocker.