Old Mill stoves were made by Devault Fab and Welding Co., which was located in surburban Philadelphia near Valley Forge. A large variety of steel stoves with cast door were manufacturered from 1978 to 1984. Model names were OM25, OM50, OM55, OM80 (coal/wood), etc.
The stoves were made in the step top design which was first introduced by Fisher Stoves, however some models had flat tops which allowed them to fit into fireplaces more easily.
PDF Spec Sheet on Old Mill WOOD-COAL OM 80 Model - http://hearth.com/images/uploads/oldmillstove80.pdf
Spec sheet on Old Mill OM55 Insert - http://hearth.com/images/uploads/om55.pdf
The stoves were made in the step top design which was first introduced by Fisher Stoves, however some models had flat tops which allowed them to fit into fireplaces more easily.
PDF Spec Sheet on Old Mill WOOD-COAL OM 80 Model - http://hearth.com/images/uploads/oldmillstove80.pdf
Spec sheet on Old Mill OM55 Insert - http://hearth.com/images/uploads/om55.pdf