SummerCool 21" Lawn Mower Blade DWO1DT233 Compatible with Dewalt MDT Troy Bilt,Replaces for 742P05642 742-05642 SCP21E,S Shape Center Hole,2 Pack | Diamond Hole Compatible with S-Pattern Blade Spindles

What It Is

This is a 21-inch S-shaped lawn mower blade sold as a 2-pack, designed for mid-size walk-behind mowers. It’s intended as a replacement for OEM blades on compatible Dewalt, MDT, and Troy-Bilt models, and works with diamond-hole spindles that accept S-pattern blades.

Fitment & Compatibility

Before buying, confirm these three things:

• Deck size: Blade length is exactly 21 inches. Measure your current blade tip-to-tip; it must match. This fits 21-inch cutting decks.
• Center hole: Uses an S-shaped center hole (diamond-shaped opening) for S-pattern spindles. Will not fit round or star-shaped spindles. Check your spindle’s hole geometry.
• OEM replacements: Replaces Dewalt part 742P05642, 742-05642, and Troy-Bilt SCP21E. Also fits some MDT models. If your mower uses any of these OEM numbers, this blade is a direct swap.
• Brand/model: Primarily for Dewalt, MDT, and Troy-Bilt 21-inch mowers. Not universal—verify your model against the compatibility list on the packaging or seller’s fitment chart.

Key Things to Know

• Quality: Made from heat-treated steel. 4.4 stars from 14 reviews suggests decent durability for residential use, but not as thick as premium aftermarket blades.
• Installation difficulty: Easy if you have a socket wrench and blade removal tool. Use thread locker on the bolt and torque to spec (typically 30-40 ft-lbs). Sharp edges—wear gloves.
• Common gotcha: The S-hole must align exactly with your spindle. If your mower uses a different hole pattern (e.g., star or oval), this blade will not mount securely.
• Pack size: Two blades in the box. Only replace both if both are worn; otherwise, keep one as a spare.

Should You Buy It

Buy this if you own a 21-inch Dewalt, MDT, or Troy-Bilt mower that uses S-pattern spindles and OEM parts 742P05642 or SCP21E. It’s a good value for a 2-pack, but double-check the center hole shape first. If your spindle is round or star-shaped, look elsewhere.