2026-09-05
The coulter is the first soil-engaging part on a no-till drill or planter. It slices residue and opens a slot ahead of the seed opener. Wrong diameter or edge and you get hairpinning, slot closure or premature wear. Here is the short guide.
Smooth (plain) gives a clean slice with minimal soil disturbance. Best for low-residue fields and shallow placement (1-3 cm).
Ripple (wave) / fluted is aggressive cutting that lifts residue into the slot to improve seed-to-soil contact. Best for high-residue, no-till corn and soybean.
16 inch is standard for most planters and light drills. 17 inch is popular for no-till drills (John Deere 750, Great Plains). 18 inch is common on heavy-duty no-till. 20 inch is for fertiliser coulter / large no-till drill. Larger diameter means more momentum, better residue cutting.
3 mm (light duty), 4 mm (standard), 5 mm (heavy / stony). Heavier is more durable but takes more weight to penetrate.
Boron steel 28MnB5 / 30MnB5, 42-52 HRC. Standard for OEM replacement.
Most coulters use a sealed bearing in a replaceable hub. Confirm bore size (16 mm, 5/8 inch, 3/4 inch) and bolt pattern before ordering.
Bottom line: Match edge + diameter + thickness + steel + hub bore. Send OEM code and we confirm within 24 hours.