(OCN) 391-612 Oregon Mulching Blade Gator G6 21-9/16" Replaces Kubota K5559-34330 + Other Models

What It Is

The Oregon Gator G6 mulching blade (model 391-612) is a high-lift, multi-serrated blade designed to shred clippings into fine mulch for improved lawn health. It fits 21-9/16" decks and is a direct replacement for the Kubota K5559-34330, plus several EGO models.

Fitment & Compatibility

• Deck size: 21-9/16" (548mm) cutting path – measure your existing blade from tip to tip to confirm.
• OEM cross-references: Kubota K5559-34330, EGO 2822131001 (fits select EGO 56V mowers like LM2100SP, LM2101, LM2102SP). Verify your model against Oregon’s fitment list.
• Center hole: 7/8" (22mm) round – common for many push mowers.
• Blade thickness: 0.100" (2.5mm) – check your deck’s spindle clearance for proper fit.
• Always remove the battery and spark plug before swapping blades. Use a torque wrench to tighten to 30-40 ft-lbs.

Key Things to Know

• Mulching performance: The G6’s “Gator” teeth and curved wings create more lift, producing finer clippings than standard flat blades – good for bagging alternative.
• Build quality: Heat-treated steel with a corrosion-resistant coating. Holds an edge longer than many OEM blades, but sharpening requires a file or grinder (not a bench grinder) to avoid overheating.
• Installation: Requires a 15/16" socket or wrench. No blade balancer needed – Oregon pre-balances these. Check blade orientation: the curved wings face upward toward the deck.
• Common gotcha: This blade is slightly heavier than some OEM blades (0.9 lb vs 0.7 lb), which may slightly reduce runtime on battery mowers. Verify your deck’s spindle can handle the extra mass.

Should You Buy It

Buy this if you want superior mulching on a compatible EGO or Kubota mower, especially if you’re tired of clumping or want to skip bagging. Avoid if you need a standard lift blade for bagging or if your deck is under 21” – it won’t fit. At $46.45, it’s a premium upgrade that lasts.