Pressed shape steel, made of a low cost general steel material that is not
hardened, forms a frame with long grooves cut therein. Guide rails, made
of a specialized steel material that can be subjected to a hardening
treatment, are hardened. Thereafter, outer surfaces of the hardened guide
rails are ground and the guide rails are integrally joined in the long
grooves. Ball-rolling grooves are formed in the guide rails, thereby
completing a guide-equipped frame for an actuator. Because the general
steel material and the specialized steel material are principally ferrous
materials, both exhibiting a Young's modulus at or above 170 GPa with
substantially the same coefficient of linear thermal expansion, the frame
needn't be increased in size or have a complex internal structure to
reinforce the strength of the frame, and the guide rails remain securely
retained in the grooves even if the actuator experiences changes in
temperature.