The wrench afforded the Dominys a heavy lever with which large nuts or bolt heads could be loosened or tightened. Wheelwrights, for example, would have needed a wrench because, as Martin indicated in 1813, "the external ends of axle-trees…are generally formed into screws, to which are adapted nuts."171 The loosening or tightening of a wedge permitted adjustment of the jaws on both some wrenches like that in column 3, no.2. Coach builder's wrenches were used for wheelwright's work and coach repair, both performed by Nathaniel Dominy V.