Ketofa AC04029 Lawn Mower Blade Replacement for RYOBI 20" 40V Brushless Mowers, Fits RY401170 RY401180 RY401017 RY401018, Half-Moon & Square Center Hole, 20-Inch Steel Blade

What It Is

This is a 20-inch steel replacement blade for RYOBI 40V brushless mowers, specifically the half-moon and square center hole pattern used on models like RY401170, RY401180, RY401017, and RY401018. It’s a direct aftermarket alternative to the OEM blade for mulching or bagging on residential lawns.

Fitment & Compatibility

Before buying, check three things:

• Deck size: Must be a 20-inch cutting deck (measure your mower deck width). This blade will not fit 21-inch or 22-inch decks.
• Center hole pattern: This blade uses a half-moon (D-shape) and square center hole. Verify your mower’s blade mounting bolt is compatible—most RYOBI 40V 20" models use this pattern, but some older units may have a different star or keyed hole.
• Model number: Confirmed fits RY401170, RY401180, RY401017, RY401018. Check your mower’s model sticker (under battery or on frame). This is aftermarket, not OEM RYOBI part #AC04029 (though listed as Ketofa AC04029). Expect minor finish variations but same dimensions.

Key Things to Know

• Installation: Easy—one bolt per blade. Use a torque wrench set to 30-35 ft-lbs. Reverse thread on some models? No, RYOBI 40V blades use standard right-hand threads.
• Quality: Steel is 0.125-inch thick, heat-treated. Edges may be slightly duller than OEM out of box—sharpen before first use for best cut.
• Common gotcha: The half-moon hole must align perfectly with the mower’s adapter plate. If it’s loose or doesn’t sit flush, the blade will wobble—return it.
• Balance: Check blade balance after sharpening. Many aftermarket blades need light grinding on the heavy side to prevent vibration.

Should You Buy It

If you own a RYOBI 40V 20" brushless mower from the listed models and need a budget-friendly replacement that matches OEM dimensions, this works. It’s not sharper or longer-lasting than the original, but it’s a direct fit at a lower price. Skip it if you want a premium, pre-sharpened blade or have a different deck size or hole pattern.