Convert from obolus [Ancient Rome] to truss

Unit Definition (obolus [Ancient Rome])
The obolus [Ancient Rome] is a historic unit of weight or mass. The obol is a very small weight that originated as the weight of a tiny Greek coin. In Rome, the obolus was equal to 1/48 Roman ounce (uncia) or about 0.57 gram.

Unit Definition (truss)
The truss is a traditional weight unit, generally equal to 4 stone or 56 pounds (about 25.4 kilograms). The truss was used primarily for measuring hay. In 1795, Parliament specified that a truss of hay should equal 56 pounds for old hay or 60 pounds (about 27.2 kilograms) for new hay.