What is a black ball maker? The OED says a black ball is
Any of a number of black-coloured balls of wood, ivory, etc., used to record an adverse vote in a ballot; (hence) an adverse secret vote; the vetoing of (an applicant's) membership or inclusion.
So, was Mr. Pollock primarily engaged in creating these voting emblems? It seems to me a very specific object, and one that wouldn't garner an income of substance. What was the demand for black balls? How many of them were in circulation? Who would have been buying them? Or, am I way off base here and a black ball maker had nothing to do with black balls?
**On Nov 9, a brief discussion of the black ball makers erupted on Twitter between me, Chad Black and David McKenzie. Here are the posts, which include links to some great citations Chad found on Google Books.