I have one of the MW (Montgomery Ward) models that were sold by National. It was designed by the Portman Sewing Machine Company. The design has been referred to as “Seamstress”, “N-50”, and “Model J”. I’m not clear on which name was used by which entity. I think mine is possibly called a Model J because it has the serial number of J 30719.
I removed the motor of mine and experimented with adapting the machine for use in a treadle cabinet, but I didn’t get very far. The base housing interferes with the belt path, and I will have to figure out some type of idler pulley mounted on the treadle top to avoid it. The project is on hold, but I still think it would make a good darning machine for mending jeans and other denims. That’s what I was hoping to use mine for....
CD in Oklahoma