A method of constructing an electric linear displacement motor for use in a testing device includes providing a stator having as stator housing with internal coils and a through bore extending from a first end of the stator housing to the second end of the housing. First and second end supports are connected to the first and second ends of the stator housing. An armature having magnets retained therein is inserted into the stator housing such of the armature is supported by the first end support and the second end support. A plurality of set screws are inserted into threaded openings proximate both the first end and the second end of the housing. The set screws then support and retain the armature such that there is an annular gap between the armature and the coils.