I used a 4” pipe cutter to cut and rotate my 1985 axle. Rented it from some tool shop, and then used two 6’ bars, one in each end, to bust loose and turn each knuckle. Do one side first, and re-weld, then the other.
Heaving on these 6’ bars was how I got to know my young wife. Recommended.
Turning knuckles is surprisingly easy to do well, at a technical level. The pit I fell into was not measuring carefully enough, and thinking more turning is better. It’s not. Measure your angles carefully while the springs are under full load, and DO NOT second guess yourself later. A number is a number; respect it. Years later I converted back from a high pinion to a low pinion (partly to correct my over-zealous angle, and partly to stupid-simplify my truck.)