M170642 Gator Mulching Blades for 42" Deck, Compatible with John Dee-re Z315E Z320M Z320R Z335E Z335M Z345M Lawn Mower, Replace UC22008, M170639, GY20683, 2 Pack

What It Is

This is a 2-pack of Gator mulching blades designed for 42-inch cutting decks, specifically engineered to fit select John Deere Z300 and Z300E series zero-turn mowers. They replace OEM part numbers UC22008, M170639, and GY20683, and are intended for mulching grass clippings into fine particles to eliminate bagging.

Fitment & Compatibility

Before buying, verify your mower deck is exactly 42 inches (measured blade tip to tip). This set fits John Deere models Z315E, Z320M, Z320R, Z335E, Z335M, and Z345M — but not other Z-series or non-Deere decks. Measure your existing blade’s length, center hole diameter (typically 1-inch), and thickness. These are aftermarket replacements; OEM parts may have slightly different balance or steel hardness. Check that your deck uses a 2-blade system (some 42” decks use 3 blades). Confirm spindle shaft size (likely 7/8-inch) and ensure the blade adapter aligns.

Key Things to Know

• Mulching performance: The Gator design uses curved wings and a serrated edge to shred clippings. Works best with dry grass; wet or tall grass may clump.
• Installation difficulty: Easy for DIY (socket wrench, blade removal tool). Torque bolts to 70-90 ft-lbs. Use thread-locker to prevent loosening.
• Quality concerns: 3.8/5 rating suggests some users report vibration or balance issues out of box. Check blade balance before installing (cheap balancer or nail-in-wall test).
• Durability: Aftermarket steel may dull faster than OEM. Expect to sharpen or replace more often if mowing frequently or on rough terrain.

Should You Buy It

This is a budget-friendly mulching upgrade for DIY homeowners with the exact Deere models listed, who want finer clippings without bagging. Skip it if you need OEM durability for commercial use, or if your deck isn’t 42 inches — fitment is narrow. If you’re okay with occasional balancing tweaks, it’s a solid value for the price.