M170642 Mower Blades for 42" Deck Compatible with John Dee re X330 X350 X354 X370 X380 Z335E Z335M Z345M Z345R, 2 Pack

What It Is

This is a 2-pack of 42-inch deck mower blades designed for select John Deere lawn tractors and zero-turn mowers. They are an aftermarket replacement for cutting grass and mulching on residential properties.

Fitment & Compatibility

Before buying, confirm your mower’s deck size is exactly 42 inches (measured blade tip to tip). This set fits John Deere X330, X350, X354, X370, X380, Z335E, Z335M, Z345M, and Z345R models. Check your owner’s manual for OEM part number M170642 or cross-reference with existing blades. Measure blade length, center hole diameter (typically 1 inch), and thickness (about 0.25 inches) to match. Aftermarket blades may vary slightly from OEM—verify bolt pattern and lift shape if you have a mulching kit.

Key Things to Know

• Quality: Made from hardened steel, but may dull faster than OEM John Deere blades. Inspect for burrs or uneven edges before installation.
• Installation: Easy with a socket wrench and torque wrench (tighten to 70–90 ft-lbs). Use thread locker on bolts to prevent loosening.
• Common Gotchas: These are not for 48-inch or 54-inch decks. Do not mix with OEM blades on the same spindle—balance will be off. Sharpen after 25 hours of use for best cut.
• Pack: Two blades included, but some 42-inch decks require three blades (check your spindle count; most listed models use two).

Should You Buy It

Buy these if you need a budget-friendly, direct-fit replacement for your 42-inch John Deere X300/Z300 series mower and are comfortable with minor quality trade-offs from OEM. They work fine for regular residential mowing but may need more frequent sharpening than premium options.