Maxpower 331737B Mulching Blade for Many 21 in. Cut Craftsman, Husqvarna, Poulan Mowers, Replaces OEM no. 165833, 175052, 406712, 532175064, 594893001, 175064

What I tested and why it matters

I bolted the Maxpower mulching blade onto a 21-inch Craftsman walk-behind and spent multiple mowings pushing it through spring growth, late-summer dryness, and a weekend of leaf cleanup. I wanted to see three things: how cleanly it cuts, how well it actually mulches, and whether it installs and balances as smoothly as a good replacement blade should. This blade is a single, made-in-USA replacement with a 5/8-inch center hole that’s designed to meet or exceed the common OEM specs for many Craftsman, Husqvarna, and Poulan mowers. On paper, that’s a straightforward promise; in the yard, small details make the difference.

Fit and compatibility

Before buying any blade, I always confirm two things:
- The OEM part number from the mower’s manual matches one of the replacement numbers.
- The center hole and overall length/width match the mower’s spindle and deck.

This blade uses a 5/8-inch center hole and is sized for 21-inch decks. On my Craftsman setup, the fit was exact—no slop, no shimming needed. If your mower uses adapters or a different arbor style, check your manual and the OEM list carefully; the simplest compatibility check is verifying your OEM number against Maxpower’s list. As a general rule, if your deck is 21 inches and your spindle uses a 5/8-inch round mount compatible with the listed OEMs, you’re in good shape.

Installation and setup

Installation is routine but worth doing right:
- Disconnect the spark plug wire.
- Tip the mower with the carburetor up to avoid flooding.
- Wedge a block of wood in the deck to keep the blade from spinning.
- Clean the mounting surfaces so the blade seats flat.
- Torque the bolt to your manufacturer’s specification.

The blade arrived straight and true. Out of the box, the edge had the typical factory bevel—not razor-sharp, which is normal (a slightly thicker edge holds up better to sand and small debris). I checked balance on a cone balancer; it sat level with no correction required. If you don’t have a balancer, at least do a quick nail test to make sure one end isn’t significantly heavier.

One easy installation mistake is orienting the blade upside down. The cutting edge has a distinct bevel that should face the direction of rotation so the sharpened edge meets the grass first. Likewise, the raised “lift” edge belongs up toward the deck.

Cutting and mulching performance

With the Maxpower blade, my first pass through moderately tall fescue produced a noticeably finer clipping size than a standard straight blade. The mulching profile recirculates clippings inside the deck longer, and it shows—stragglers were minimal and the turf finished with an even, well-groomed look.

• In average weekly growth, it leaves a clean cut with very little fraying at the tips.
• In heavy, damp grass, I needed to slow my walking pace a touch to let the blade process clippings; when I did, clumping was kept to a minimum.
• For leaf season, the blade chopped leaves into small fragments that disappeared into the canopy after two passes.

If you primarily bag, know that mulching blades generally have less lift than high-lift bagging blades. I could still bag when needed, but the chute didn’t “pull” quite as aggressively as it does with a dedicated bagging blade. As a side-discharge blade, it’s competent, though discharge distance is shorter than a true high-lift profile.

Smoothness and noise

I pay attention to vibration because it translates into fatigue and bearing wear. This blade ran smoothly on my mower—no rattle, no edge wobble. Noise levels were typical for a mulching profile: slightly more of a “whoosh” under the deck compared to a flat blade, which is expected because of the additional air movement to recirculate clippings. Nothing stood out as loud or harsh.

Durability so far

The steel thickness feels substantial in hand, and edge retention after several mowings was in line with other quality aftermarket blades I’ve used. I expect to touch it up a couple of times per season, which is normal for sandy soil or occasional twig contact. A reminder: lawn mower blades are not brush blades. If you run over hidden stumps, rocks, or thick brush, any residential blade can bend or nick. For turf care, the Maxpower holds up well; for trails or rough pasture, use the right tool.

Maintenance and sharpening

Out of the box, the edge was serviceable. For the best cut quality, I gave each edge a light pass with a file to refine the micro-bevel and then rebalance. A couple of notes:

• Maintain the factory angle (usually around 30 degrees) and avoid creating a thin, brittle edge.
• Don’t grind so hard that you blue the steel; overheating softens it.
• Keep both ends within a gram or two of each other to minimize vibration.

I like to check the edge every 6–10 hours of mowing, more often if you mow in sandy conditions or after lawn projects that leave grit on the surface.

Real-world trade-offs

No blade does everything perfectly, and this one is no exception:
- Mulching: Excellent for weekly mowing and leaf shredding, provided you manage your pace in heavy or wet conditions.
- Bagging: Works, but a high-lift bagging blade will pull clippings into the bag more efficiently.
- Side discharge: Adequate; the throw isn’t as far as a high-lift blade.
- Impact resistance: Good for turf; not intended for brush or stumps.

Those are typical mulching-blade trade-offs, and they’re worth understanding up front.

Value and what you’re paying for

This is a single replacement blade that meets common OEM specs and is made in the USA. Compared to many OEM blades, the Maxpower is often priced lower while matching fit and performance for routine residential mowing. The balance out of the package and the consistent cut quality are what stood out most in my use. If you want a set for a dual-blade deck, you’ll need to buy two; for single-blade 21-inch mowers, this is a straightforward swap.

Tips to get the most from it

• Verify compatibility by OEM number and center hole size before ordering.
• Keep your deck clean—mulching performance depends on airflow.
• Mow more frequently in peak growth; mulching blades are happiest with 1/3-of-blade-height cuts.
• Touch up the edge periodically and check balance after sharpening.
• Torque the blade bolt to spec and recheck after the first mowing.

Who it’s for

• Homeowners with 21-inch Craftsman, Husqvarna, or Poulan mowers that use a 5/8-inch center hole and one of the listed OEM numbers.
• Anyone who mulches regularly and wants finer clippings and better leaf reduction without jumping to a premium-priced OEM blade.
• Users who occasionally bag but mostly mulch and are comfortable with basic maintenance like sharpening and balancing.

If your priority is maximum bagging airflow or you routinely tackle tall, wet, neglected grass, a dedicated high-lift or even a “rough cut” setup might be a better fit. For well-tended lawns and leaf season, this blade hits the sweet spot.

Bottom line

The Maxpower mulching blade did what I expect a good aftermarket blade to do: it fit correctly, ran smoothly, and produced a fine, even cut with noticeably improved mulching versus a standard blade. It arrived straight and balanced, benefited from a light edge touch-up, and held up well under normal residential use. It won’t turn a mower into a brush cutter, and it’s not the best choice if bagging performance is your top priority, but as a general-purpose mulching blade for a 21-inch deck, it’s a strong performer.

Recommendation: I recommend this blade for homeowners looking to improve mulching quality on compatible 21-inch Craftsman, Husqvarna, and Poulan mowers. It offers reliable fit, smooth operation, and fine clippings at a fair price, with the added reassurance of being made in the USA. If you sharpen and balance it properly and pair it with sensible mowing habits, it’s an easy upgrade that pays off in a cleaner lawn and less bagging.