A medical electrical lead includes a threaded conductor, a coil conductor, and a sleeve. The threaded conductor has an outer surface with a threaded section that includes threads defining grooves between the threads. The coil conductor has coils seated in the grooves of the threaded conductor. The coil conductor has a coil major diameter greater than a thread major diameter. The sleeve is positioned radially outward of the coil conductor and has an inner surface in contact with the coil conductor so as to produce a radially inward force compressing the coil conductor against the threaded section of the threaded conductor.