The GK18 projector mechanism was made by the Kershaw Company in Leeds and was an improved version of the GK40, a machine that was produced for the Indian market during WW2 years at low cost and in a cheap crinckle/crackle finish. First used for gun training, it was not sold in the UK for use in cinemas, but used in mental hospitals by the newly formed NHS. With financial constraints, the installations consisted of only one machine with a second added in later years.
The reliability of the machine led the Rank Organisation to issue a low cost assembly designated as the GK18, the mechanism being a GK40 with improved gate and the whole finished in a mid stone hammer paint.