Machine and method for deep rolling fillets of split-pins of engine crankshafts. Each split-pin comprises neighboring and arcuately offset crank pins connected between counter weights and has a centralized splitter fence which receives side loads from the connecting rods. Annular fillets are formed between the pins and opposite sides of the splitter fence as well as between the fillets and their associated counter weights. Limbs of the fillets at the splitter fence that describe the overlap of the split-pins are deep rolled with a high load for improving yield strength while the remaining arcuate portions of the fillets are rolled at lower loads to improve strength without undue distortion of the fence. The overlap of pin to main journals can also be rolled with increased load for increased yield strength.