Abstract: A drilling motor includes a non-elastomeric stator and rotor which are dimensioned for negative or zero interference. The amount of negative interference between the rotor and the stator is determined by the largest solid particle expected to pass through the motor. The negative interference or gap between the rotor and the stator is preferably at least two times the greatest particle size. According to the invention, stators are made by machining or casting stainless steel and are fabricated in sections having lengths of 20 to 40 centimeters. The sections are indexed so that each section may be properly aligned with another. The sections are aligned and welded together to form a motor stator of conventional length.