Forged Billet 4340 aircraft quality steel Rods Features: - Material: Precision forged 4340 EN24 aircraft chrome moly quality steel. - Hardness after quenching and tempering is HRC35-38. - 3-D design offers the advantages of reduced weight without sacrificing strength. - 2 piece forging for increased strength. - Silicon bronze bushings for floating piston pins. - Each forging is X-rayed, sonic tested and magnafluxed. - Special Dowelled Cap for precision fit. - Shot peened to relieve stress. - Fully CNC machined on all surfaces to produce the lightest and strongest rod. Machining Tolerances: Big End and Small End Tolerance: <= +/-0.00017" Verticality, Parallelism and Distortion: <= +/-0.00018" Center to Center Distance Tolerance: <= +/-0.001" Sets weight matched to +/-1 gram.