The galley has walls on three sides: two long sides and one short end. The other end is open, to receive the slice. It is constructed with a pine floor and hardwood sides (apparently walnut and/or oak). The box is part of a tongue-and-groove composition: that is, the outer sides of the walls rise straight, but the inner edges are notched or rabbeted out at the floor, to permit the slice to slide into position. The pine floor is held to the side and end walls with 11 large (3/8-inch diameter) screws. The outer edge of the side walls has a rounded profile, cut with a moulding plane. The end wall, which appears to be a replacement, has a canted outer edge.

The floor board is 1/2 inch thick, the side walls are 3/4 inch thick.

A 1684 illustration of "The sliding a Page of the Slice" from Joseph Moxon's Mechanick Exercises or the Doctrine of Handyworks Applied to the Art of Printing shows how a galley and slice were used. According to The Franklin Institute records, this galley is believed to have been used in the shop of Benjamin Franklin in Philadelphia.

A former Franklin Institute accession number 3280 is painted in white ink or paint on the underside.