2026-09-05
Disc harrow blades are the most replaced wear part on tillage equipment. Get the size, steel grade or edge profile wrong and you either wear out twice as fast or buy a blade that does not match your disc gang. Here is a concise field guide.
Standard sizes are 16 inch, 18 inch, 20 inch, 22 inch, 24 inch. Measure an old blade or your disc gang specification. Mixing diameters in the same gang will produce uneven tillage depth.
Notched (serrated) edges bite better in hard, dry or trashy soils. Smooth edges give a cleaner finish and last slightly longer in soft soils. Use notched for primary tillage. Use smooth for secondary / seedbed prep.
65Mn spring steel is the workhorse, 40-50 HRC, affordable. Boron steel 28MnB5 / 30MnB5 has higher impact resistance and longer life in abrasive / rocky soils, costing 30-50% more. Pick boron if you have stones.
Thickness 3 / 4 / 5 / 6 mm. Heavier blades keep shape longer under load. Convexity 100 / 110 mm. Match your disc gang concavity.
For John Deere, Case IH, Kuhn, Lemken, Massey Ferguson, send the OEM code stamped on the old blade. We confirm the exact replacement or an equivalent cross-reference.
Bottom line: Match diameter + edge + steel + thickness + bolt pattern. Send us the OEM number and we confirm the match within 24 hours.