Push Reel Mower Selection and Bedknife Sharpening Guide

The Mechanical Advantage: Reel vs. Rotary Cutting

While rotary mowers dominate the suburban landscape by violently chopping grass with a high-speed horizontal blade, a push reel mower operates on a fundamentally superior mechanical principle: the scissor cut. As the rotating cylinder (reel) pushes the grass blade against the stationary bottom blade (bedknife), the tissue is sheared cleanly. This precise cut seals the grass blade's cellular structure, drastically reducing moisture loss and minimizing the entry points for fungal pathogens like brown patch and dollar spot.

According to turfgrass research from the University of Minnesota Extension, clean mowing cuts are critical for maintaining turf density and reducing environmental stress. However, achieving this scissor cut requires exact tolerances and proper equipment selection based on your specific turfgrass species.

Matching Blade Count and Width to Your Turfgrass

Not all manual cylinder mowers are built for every lawn. The number of blades on the reel dictates the "frequency of clip"—how many times the reel cuts per inch of forward travel. Low-cut, dense grasses require a higher frequency of clip to prevent the blades from pushing the grass over rather than cutting it.

Selection Insight: If you maintain a thick Tall Fescue lawn at 3.5 inches, a 7-blade reel will actually clog and stall because the frequency of clip is too high for the long grass volume. Stick to a 5-blade reel with a chain-drive system (like the Fiskars InertiaDrive) to maximize torque through thick, cool-season blades.

Mastering the Bedknife: Adjustment and Backlapping

The most common failure mode of a push reel mower is not dull blades, but improper bedknife alignment. The gap between the reel and the bedknife must be between 0.001 and 0.002 inches. If the gap is too wide, the grass tears; if the blades touch continuously, you create immense friction, destroying the bearings and dulling the edges prematurely.

The Backlapping Procedure

Backlapping is the process of applying an abrasive compound between the reel and bedknife and running the reel in reverse to hone both edges simultaneously. You should backlap your mower every 15 to 20 hours of use, or whenever the mower begins to "tail" (fold grass over instead of cutting).

1. Clean the Assembly: Use a wire brush and degreaser to remove all dried grass sap and debris from the reel and bedknife.
2. Apply Lapping Compound: Paint a thin, even layer of 120-grit silicon carbide lapping compound (such as Clover Brand) onto the bedknife edge. Use a 220-grit compound for a finishing polish if the blades are already in decent shape.
3. Reverse the Rotation: Using the provided hand crank or a cordless drill on a very low speed setting (under 300 RPM), turn the reel backwards. Looking at the mower from the right-side drive gear, this means turning the reel counter-clockwise. Run for 3 to 5 minutes.
4. The Paper Test: Wipe away the compound. Take a standard strip of 20lb copier paper and pull it across the entire width of the bedknife while slowly rotating the reel forward. The paper should slice cleanly with a crisp "snick" sound. If it snags or folds, adjust the bedknife tensioning screws at the ends of the cutting bar by a quarter-turn and repeat.
5. Protect the Steel: Wash the reel with water, dry immediately, and spray with a light silicone lubricant or WD-40 Specialist to prevent flash rusting.

Troubleshooting Common Reel Mower Failures

Even with meticulous maintenance, manual mowers present unique mechanical challenges. Understanding these failure modes will save you from unnecessary part replacements.

Symptom: Grass Tearing or "Tailing"

Cause: The bedknife is set too low, or the reel-to-bedknife gap is wider than 0.003 inches. This is highly common when mowing wiry grasses like Zoysia or mature Bermudagrass.
Fix: Loosen the bedknife lock nuts and turn the adjustment screws clockwise to raise the bedknife closer to the reel. Re-test with the paper strip. If backlapping does not resolve the tearing, the reel may have suffered "coning" (uneven wear where the center of the cylinder is thinner than the ends), which requires professional cylindrical grinding.

Symptom: Streaking and Uncut Ridges

Cause: Overlapping wheel tracks or a bent bedknife. If the bedknife has bowed downward in the center due to impact with a hidden root or rock, it will leave a ridge of uncut grass directly in the middle of your swath.
Fix: Remove the reel and inspect the bedknife with a straight edge. A slight bow can sometimes be corrected by carefully tapping the center of the bedknife upward with a brass drift punch and a rubber mallet, but severe bends require ordering a replacement cutting bar.

Symptom: Mower Jams or Locks Up

Cause: Reel mowers lack the brute force of gas-powered rotaries. A single thick weed stem, a fallen twig, or a dense patch of clover can wedge between the reel and bedknife, locking the drive gears.
Fix: Never force the mower forward, as this will strip the pinion gears. Engage the parking brake (if equipped) or block the wheels, then use a wooden dowel to manually reverse the reel and dislodge the debris. As noted by Penn State Extension, maintaining a weed-free lawn is significantly easier when using manual equipment, as reel mowers struggle to slice through thick, broadleaf dicot stems.

Frequently Asked Questions

Can I use a push reel mower on wet grass?

You can, but it is not recommended. Wet grass clumps together, forming a thick mat that pushes down rather than standing upright for the scissor cut. Furthermore, moisture accelerates the corrosion of the high-carbon steel reels and bedknives. If you must mow after a morning dew, immediately hose off the cutting chamber and apply a silicone spray afterward.

How often do the bearings need lubrication?

Most modern push reel mowers, like the Fiskars StaySharp line, feature sealed ball bearings that require zero maintenance for the life of the mower. However, older or budget models (like standard Scotts or generic hardware store brands) use bronze sleeve bearings. These must be greased with a lithium-based white grease or SAE 30 non-detergent oil at the zerk fittings every 10 hours of operation to prevent the reel from binding.

Is a reel mower better for the environment?

Beyond the zero-emissions benefit of manual labor, reel mowers promote a healthier soil microbiome. The clean cut reduces turf stress, which in turn reduces the need for synthetic nitrogen fertilizers and chemical fungicides. A healthy, densely rooted lawn managed by a reel mower sequesters more carbon and requires less supplemental irrigation during peak summer heat.