A method of manufacturing, extruding, milling and welding a high torque, thin monolithic walled guiding catheter having resilient reinforcement material (8, 23, 29, 70, 73) integrally spiralled or braided into monolithic walls (21) of flexible material. A solid lubricant, also referred to as dry lubricant, comprised of either special fluorine containing materials or polymeric organic silicon compounds is embedded into interior and exterior wall surfaces of the catheters. Smooth interior walls (11) are channeled (10) to decrease friction resistance, to trap resistance particles and to dissipate friction heat in the high ratio of surface area to cross-sectional area of small catheters. Number of spirals or braids of reinforcement strands per unit of length, number of layers of strands of the catheters, catheter diameter and progressiveness thereof are designedly different for separate portions of particular catheters. Catheter tips (6) arc machinable immediately adjacent to select density of strands of reinforcement material. Perfusion ports are machinable where desired. Directional bends (7) are positional selectively at distal ends (5) of the catheters (1).