OK Engine Company was formed in 1975 as a spin off of the Herkimer Tool and Model Works, a manufacturer of high quality metal parts. The Herkimer companys' product line of OK Cub model airplane engines and OK Streamliners model train cars are now manufactured by OK Engine Company in the USA. The product line has been improved and expanded to include custom metalworking services and repair services for some of the two million model products made by the two companies since 1938. OK also maintains a parts service for their older products and a company museum on site which is open by appointment.