2 Replacement Bush Hog Rotary Cutter Blade 20-3/4" x 4" x 0.5" w/ 1.5" Hole CW 86665BH Review

Overview

If you’re maintaining serious acreage with a Bush Hog rotary cutter, you know that blades are the heart of the operation. This 20-3/4" x 4" x 0.5" replacement blade with a 1.5" center hole (CW rotation, model 86665BH) is built for heavy-duty brush and pasture mowing. It’s designed for owners of Bush Hog brand rotary cutters—or compatible models—who need a direct, no-fuss replacement that can handle thick saplings, overgrown fields, and tough weeds season after season.

Who Should Buy This

• Ranchers and large-property owners managing 5+ acres of pasture, trails, or fence lines. This blade’s thickness and width are overkill for a suburban lawn but perfect for cutting through woody brush and tall grass without bending.
• Farmers and land managers who use a Bush Hog rotary cutter (or equivalent) for routine field maintenance. If you’re replacing worn or damaged blades on a 5- to 8-foot cutter, this is a direct match for the 86665BH spec.
• DIYers who prefer OE-style replacements over generic or universal blades. The exact hole size, length, and thickness mean no drilling, no adapters, and no guesswork—just bolt on and go.
• Owners of older Bush Hog models looking for a reliable, aftermarket alternative to OEM pricing. This blade offers the same dimensions and weight as the original, often at a lower cost.

Key Features Breakdown

• Length: 20-3/4" – This is a standard size for many medium-duty rotary cutters. It provides enough reach to overlap the deck and ensure a clean cut, while not being so long that it strains the gearbox in heavy conditions.
• Width: 4" – A wide blade that distributes cutting force across more surface area. It’s less prone to chipping than narrower blades when hitting rocks or stumps, and it helps mulch lighter material more efficiently.
• Thickness: 0.5" – This is the heavy-duty sweet spot. Half-inch steel resists bending under impact from saplings or hidden debris, but it’s not so thick that it adds unnecessary weight to the spindle. It’s a balance of durability and performance.
• Center Hole: 1.5" – A precise fit for Bush Hog and compatible cutter spindles that use this hole size. A snug hole reduces vibration and blade wobble, which extends the life of your gearbox and belt.
• Rotation: Clockwise (CW) – Critical for correct cutting direction. Installing a CW blade on a CCW spindle will throw debris backward and damage the deck. Always verify your cutter’s rotation before ordering.
• Model: 86665BH – This is the direct cross-reference for many Bush Hog models. Check your owner’s manual or existing blade part number to confirm compatibility.

Pros

1. Built to last – The 0.5" thickness and heat-treated steel handle repeated impacts from rocks, roots, and 2-inch saplings without bending or cracking. Users report these blades outlasting cheaper alternatives by a full season.
2. Perfect fit, zero modifications – The 1.5" hole and 20-3/4" length match Bush Hog’s factory spec exactly. No drilling, filing, or bushing required—just remove the old blade and bolt this one on.
3. Excellent balance – These blades come matched in weight and shape, which minimizes vibration at high PTO speeds. A smoother-running cutter means less fatigue on your tractor and your ears.
4. Sharp out of the box – The cutting edges are ground clean and sharp enough to slice through grass and light brush immediately. You can start mowing right away without a trip to the bench grinder.
5. Reasonable price for heavy-duty quality – At $160, this is competitive with OEM blades that often cost 20-30% more. You’re getting commercial-grade steel without the dealer markup.
6. Consistent manufacturing – Each blade is punched and heat-treated to the same spec, so you can buy a set and trust that both blades will wear evenly. No surprises.

Cons

1. Not for every cutter – Despite the “Replacement” branding, this blade only fits cutters with a 1.5" center hole and CW rotation. If your spindle uses a different hole size or rotates CCW, you’ll need a different part.
2. Heavy – At roughly 8–10 pounds per blade, a set of two adds significant weight to the cutter. That’s fine for a 60+ HP tractor, but smaller subcompact tractors may struggle with the extra inertia, especially in thick brush.
3. No warranty information provided – At this price point, some buyers expect a limited warranty against defects or premature wear. The listing doesn’t mention any, so you’re relying on the product’s reputation.
4. Limited availability – This model can be harder to find in stock than more generic sizes. If you need blades in a hurry, you might have to wait for a restock or pay expedited shipping.

Bottom Line

If you own a Bush Hog rotary cutter that uses a 20-3/4" blade with a 1.5" center hole and clockwise rotation, this replacement set is a no-brainer. It delivers the same durability and fit as the OEM part at a more palatable price, with the added benefit of being sharp and balanced from the factory. It’s not for every mower—check your specs carefully—but for ranchers, farmers, and serious property owners who need a reliable brush-cutting blade, this is a solid investment. I recommend it without reservation for anyone maintaining 5+ acres of rough terrain.

Frequently Asked Questions

Q: Will this blade fit my Bush Hog model 3210?
A: Possibly. The 3210 uses a 20-3/4" blade with a 1.5" hole, but you must verify the rotation direction. Most Bush Hog cutters in this size range are CW, but some older or specialty models may differ. Check your owner’s manual or look at the existing blade’s rotation direction (the cutting edge should point forward when the blade is installed correctly).

Q: Do I need to replace all blades at once?
A: It’s strongly recommended. Replacing only one blade throws off the balance, causing vibration that can damage the spindle and gearbox. Always replace blades in pairs (or sets for multi-spindle cutters) to maintain even wear and smooth operation.

Q: Can I sharpen these blades when they dull?
A: Yes, but with caution. These are 0.5" thick, so you’ll need a heavy-duty grinder or bench grinder. Avoid overheating the edge, which can soften the heat-treated steel. Many owners find it easier to replace them outright once they’re significantly dulled, given the price point.