Isaac Jefferson was a negro (the term "slave" was used at the time) belonging to Thomas Jefferson.  He was apprenticed to a tinsmith around 1790.  He learned to make graters, pepperboxes, and tin cups.  A grater in the period could also be known as a bread rasp.  A bread rasp was used to shave off the burnt outside of the bread, which may have been saved and used in the next batch of bread.  Pepperboxes were like a pepper shaker, but there was no accompanying salt shaker as salt would cause the tin canister to rust.    It is said that Isaac made 48 cups a day.  Prior to 1804 all work would have been done with hand tools.  The step that would have taken the most time would have been the soldering.  Cutting and swaging would have gone rather quickly.

Here is a photo from the Library of Congress taken in 1845-

http://www.loc.gov/exhibits/jefferson/images/vc16.jpg

Notice his apron has a loop around his neck and his shirt is not buttoned up.