How to Use a Skid Steer Rotary Cutter (Brush Hog)

Step 1: The Pre-Cut Site Walk — Non-Negotiable

Before a rotary cutter blade spins, you walk the site. This is not optional. A rotary cutter blade runs at high speed and will throw anything it contacts — rocks, wire, chain, fence staples, pieces of metal pipe — at lethal velocity. The pre-cut walk is how you find those hazards before the machine does.

Walk every part of the area you plan to cut. Look for:

• Fence posts and wire — old fencing overgrown by brush is extremely common on rural Canadian properties. Wire wraps around the spindle and can cause catastrophic failure. T-posts become projectiles.
• Rocks and boulders — surface rocks you can remove or route around, but also watch for partially buried rocks that are visible as bumps. A blade strike on a buried rock can shatter a blade, damage the deck, and throw fragments at high speed.
• Stumps — hitting a stump damages blades instantly and can crack the deck. Mark stumps with flagging tape so you can see them once you're in the cab with reduced visibility.
• Old farm equipment and debris — chain, cable, auger flighting, rebar, steel pipe. Canadian farm properties accumulate decades of buried scrap. Flag or remove everything you find.
• Irrigation lines and drainage tile — common in farm fields. Cutting over buried tile or irrigation is expensive to repair.
• People, animals, and structures — establish a 50-metre keep-clear zone before cutting begins. Post someone at the access point if needed.

Step 2: Hydraulic Flow Compatibility — Confirm Before You Connect

Rotary cutters and brush hogs are high-flow attachments. Most mid-size to large deck cutters require substantial hydraulic flow to run at proper blade speed. Confirm your machine's auxiliary hydraulic flow output against your specific cutter's requirements before connecting. Running a high-flow cutter on a standard-flow machine results in slow blade speed, poor cutting performance, and potential hydraulic overheating.

Most skid steer rotary cutter attachments require high-flow hydraulics. Check your machine's specification sheet and your cutter's manual for required GPM — these are attachment-specific values that vary by manufacturer and deck size.

Step 3: Height Setting — Don't Scalp on the First Pass

Setting the cutter height correctly before starting saves blades and produces a better cut. The instinct is to set the deck as low as possible to cut everything short in one pass — resist this.

• Start with 4–6 inches of clearance on the first pass. Especially in areas you haven't walked thoroughly, running higher on the first pass protects blades from hidden surface rocks and gives you a chance to see what's actually in the brush before running closer to ground.
• Lower on subsequent passes if needed. If the client wants a lower final cut, make a second pass at the target height after the first pass has revealed what's there and removed the heavy top growth.
• Don't run the deck dragging on the ground. This is how you hit buried rocks, damage skid pads, and waste blades. A small amount of clearance — even 2 inches — protects the deck significantly.

Step 4: Cutting Speed — Slow is Better

The most common rotary cutter mistake is running too fast. Faster ground speed feels more productive but produces a ragged, uneven cut and increases the risk of hidden hazard strikes.

• Typical effective speed range: 2–4 mph. On dense brush or heavy material, stay at the lower end. Speed up only in light, thin material where the deck isn't being loaded.
• Let the cutter work at its own pace. If you hear the engine lugging — RPM dropping significantly — you're moving too fast. Slow down until RPM stabilizes. Lugging the engine to maintain speed is how you overheat the hydraulic system and wear the engine prematurely.
• Production rate is a function of cut quality, not ground speed. A fast pass with ragged, missed spots that needs a second pass is slower overall than a slow first pass that's done.

Step 5: Overlapping Passes for a Clean Cut

Running passes with no overlap leaves thin strips of uncut material between passes — visible as rows of standing material after you're done. Plan a 10–15% overlap on each pass to ensure complete coverage.

• For a 72-inch (6-foot) deck, overlap by 7–11 inches on each pass.
• More overlap on dense material or irregular terrain; you can reduce overlap slightly in clean, thin grass.
• Mark your pass lines at the start of the job if you're cutting a large, open area — it's easy to drift off parallel and end up with inconsistent passes.

Canadian Brush Species: Know What You're Cutting

Canadian brush presents a variety of cutting challenges depending on region and species. What works well on Manitoba prairie brush isn't the same as what you'll encounter in BC river bottoms.

• Manitoba maple (Box elder): Dense, multi-stem growth that regrows aggressively. Very hard on blades — short inspection intervals are especially important when cutting this species. Common in Manitoba, Saskatchewan, and Ontario.
• Willow: Flexible stems wrap rather than cut cleanly. Can accumulate around the spindle area. Common near water in every province. Watch for wrap-around and check under the deck more frequently than usual.
• Poplar (trembling aspen, balsam poplar): Soft wood cuts easily, but high volume of stems and aggressive suckering means it regrows quickly. Cutting doesn't eliminate it — plan for multiple passes over a season if the goal is control rather than one-time cut.
• Alder (BC and coastal): Dense, fast-growing. BC river alder stands can reach 6–8 inches diameter quickly. Know your cutter's rated cutting diameter and stay within it.

Blade Inspection Schedule

Canadian brush is hard on rotary cutter blades. A blade inspection schedule that works on light grass doesn't work on mixed brush with rocks and stumps.

• Inspect blades every 4–6 hours of cutting in brush conditions. More frequently on rocky ground or when cutting species known for hidden rocks (fence lines, old pastures).
• What to look for: Chipped or cracked blade edges (replace), bent blades (replace — a bent blade causes vibration that damages the spindle bearing), missing blade sections (replace immediately and inspect the deck for damage), and blade pin wear.
• Balance matters: If blades are replaced, replace the full set on that spindle to maintain balance. Running one new and one worn blade causes vibration and bearing wear.
• Never inspect blades with the engine running. Shut down, wait for all rotation to stop completely, and apply the parking brake before going near the deck.

Slope Safety: Cross-Slope, Not Up/Down

A rotary cutter adds significant weight to the front of the machine and raises the centre of gravity. This substantially increases tip-over risk on slopes compared to operating without an attachment.

• Work across the slope (contouring), not up and down. Going up or down a slope with a heavy deck on the front significantly increases the risk of forward or rearward tip-over.
• Know your machine's rated slope angle — and reduce that rating when running a heavy front-mounted attachment like a rotary cutter. Consult your machine manual for guidance on attachment-adjusted stability limits.
• Avoid abrupt direction changes on slopes. Turning across a slope to reverse direction creates a momentary sideways loading that is more destabilizing than steady slope travel.
• If you're unsure, don't. Slopes that feel marginal with the deck raised are dangerous with it lowered. Err on the side of not cutting steep terrain with a rotary cutter.

Dry Conditions: Heat and Dust

Rotary cutting in dry conditions creates real risks that operators sometimes overlook when focusing on production.

• Fire risk. Dry cut material and a hot deck or exhaust is a fire combination. In drought conditions or fire-risk areas, avoid cutting during the hottest part of the day, have a water supply or extinguisher accessible, and watch the cut area for smoke after passes. Stop immediately if you see smoke.
• Dust. Cutting dry brush generates significant dust. On dusty days, pre-wet the cut area if possible — a light pass with a water truck before cutting keeps dust manageable. Operator breathing protection is appropriate in heavy dust conditions.
• Check under the deck for packed material buildup. Dry material packs under the deck and around spindles more quickly than green material. Check more frequently and clear it out before it causes issues.

Common Mistakes

• Skipping the pre-site walk. Every time this is skipped, it is eventually the decision that damages equipment or hurts someone. Walk the site. It takes 15 minutes and prevents multi-thousand-dollar repair bills.
• Running over stumps. Blade contact with a stump damages the blade instantly and can fracture the deck. Mark stumps during the site walk and route around them.
• Too fast for the material. Fast passes in heavy brush produce ragged cuts with missed material and excessive stress on the cutter. Slow down — the cut quality difference is immediate and obvious.
• Ignoring debris ejection clearance. Bystanders 20 metres away feel safe. They're not. Enforce the 50-metre zone.
• Skipping blade inspections. A damaged blade that runs for another 4 hours takes more with it — spindle bearings, deck structure, and sometimes the hydraulic motor — than the cost of the blade itself.
• Cutting at maximum height to avoid scalping, then never lowering. High-clearance first passes are sensible. The goal is to actually achieve a finished cut — don't leave the deck high because it's easier.