M170642 Mulching Blades Fits for John De ere Z335E Z335M Z345M Z345R X330 X350 X354 X370 X380 Riding 42 Inch Mower Deck, Replaces for UC22008, 2 Pack

What It Is

This is a 2-pack of mulching blades (model M170642) designed for John Deere 42-inch mower decks. They replace OEM part UC22008 and are intended for mulching grass clippings into fine particles that decompose quickly, eliminating the need for bagging.

Fitment & Compatibility

Before buying, verify your mower’s deck size is exactly 42 inches (measured cutting width, not overall chassis). These blades fit John Deere Z335E, Z335M, Z345M, Z345R, X330, X350, X354, X370, and X380 models. They are aftermarket replacements for OEM UC22008—check your owner’s manual or current blade part number. Measure your existing blade’s length (should be ~21 inches), width, center hole diameter, and thickness. If your deck uses a different blade length or offset design, these won’t work.

Key Things to Know

• Quality vs OEM: Aftermarket blades may use slightly thinner steel or different heat treatment. Expect slightly shorter lifespan than genuine John Deere parts, but adequate for typical residential use.
• Installation: Requires a socket wrench and torque wrench (recommended torque: 40-50 ft-lbs). Use thread-locker on the bolt to prevent loosening. Always disconnect spark plug before working under the deck.
• Balance: New blades may need balancing before installation. A simple blade balancer ($10-15) prevents vibration that can damage the spindle.
• Sharpening: These are mulching blades, not high-lift. They rely on a curved design to chop clippings—do not sharpen the top edge. Only sharpen the cutting edge at the original angle.

Should You Buy It

If you own one of the listed John Deere 42-inch deck models and want an affordable mulching blade upgrade without paying OEM prices, this 2-pack is a solid value. It’s best for homeowners who mow regularly and prefer mulching over bagging. Skip it if you need high-lift blades for bagging or if your deck is a different size.