Black & Decker MB-1800 18-Inch Replacement Blade For CM1836 and MM1800 Lawn Mowers

What It Is

This is an OEM replacement blade for Black & Decker CM1836 and MM1800 corded electric mowers. It’s a 18-inch, dual-action blade designed to lift and cut grass, then vacuum clippings into the bag—optimized for mulching on small- to medium-sized lawns.

Fitment & Compatibility

Before buying, confirm your mower deck is exactly 18 inches (measure from blade tip to tip). This blade only fits Black & Decker models CM1836 and MM1800—it will not work on other brands or deck sizes. Check your mower’s model number on the underside of the deck or near the handle. This is the genuine OEM part (part number MB-1800), so no adapter or modification is needed for these specific mowers. Verify the blade’s center hole is 1-inch diameter and the two mounting holes are 2.5 inches apart (center-to-center)—if your mower uses a different pattern, this blade won’t mount.

Key Things to Buy

• Quality: OEM blade means exact steel thickness and balance as original. Aftermarket “compatible” blades often chip sooner or throw off vibration.
• Installation difficulty: Easy—just a single bolt and washer (13mm socket). Disconnect spark plug or battery first. Torque to 30-40 ft-lbs; overtightening can strip the blade adapter.
• Common gotcha: The blade is directional—the stamped “This Side Up” must face the deck. Installing upside-down reduces cutting performance and can damage the motor.
• Sharpness: Comes sharp out of box, but the edge dulls faster on sandy or weedy lawns. Sharpen or replace every 25 hours of use for best cut.

Should You Buy It

If you own a CM1836 or MM1800 and want a guaranteed fit with no guesswork, this is the right blade. The price is higher than generic options, but the OEM quality avoids vibration, poor bagging, and premature wear. Skip it if you’re on a tight budget or need a blade for a different model—aftermarket blades exist for half the cost, but check compatibility carefully.