Adjust cutting heights of reel mowers

Properly adjusted cutting heights of your reel mowers can mean the difference between a healthy and professional-looking course and an unsightly one. Many factors are involved in keeping reel mowers properly maintained. Naturally, you must keep the bedknife and the reels razor sharp via regular grinding and backlapping as recommended by your mower's manufacturer. Sharp blades neatly cut turf, whereas dull blades tear turf, which can contribute to disease. Dull blades produce an uneven cut and finish and overwork the mower's power unit and hydraulic system.

Cutting height is important to both the look of your course and the health of your turf. Therefore, I will concentrate on the actual steps involved in setting and maintaining a consistent cutting height.

The process for adjusting fairway and greens mowers is much the same. The only significant difference is that, due to the extra-low cutting height, inaccuracies become dramatically pronounced when a greens mower is not properly adjusted. Additionally, poor adjustment generally produces fewer clippings.

* Getting started Make sure you have a height-setting bar or gauge on hand to set the bedknife at a positive cutting angle to the rollers. These devices usually come with the mower but you can get them from the manufacturer. Acu-gauges (see photo, page 36) are more accurate than height-setting bars because they can measure to a thousandth of an inch, whereas setting bars require that you perform the adjustment more by touch. However, because the turf on a fairway is not cut to the low heights of a green, a setting bar is more than adequate to ensure the fairway mower's front and rear rollers are parallel to the bedknife.

After you sharpen the reels and bedknife, assemble them into the cutting-unit frame. Using the micro-adjusters, either hand-pull or wrench back the reel to provide enough room to insert the bedknife. Mount the bedknife between the sideframes and secure it with counter-sunk-head screws, making sure they are tight enough to prevent the bedknife from moving (this is assuming reel-to-bedknife adjustment). Attach the rollers and carriages to the sideframes.

* Setting the cut You can adjust reel mowers in two ways: reel-to-bedknife or bedknife-to-reel. Either process creates the scissors-like action that cuts turf. The following procedure illustrates reel-to-bedknife adjustment.

Once you have adjusted the reel to the desired "on-cut" position, run a business card or a piece of paper across the entire length of the bedknife while turning the reel manually (see bottom photo, page 34). Be sure to wear gloves for safety and use a block of wood to turn the blades. This standard test duplicates the scissors-like cutting action of the reel and helps ensure that the right amount of friction exists between the two cutting surfaces.

There should be just enough contact between the reel and the bedknife to produce a clean cut. If adjusted too loosely, the two cutting surfaces will either bend or tear the paper. Adjusted too tightly, the surfaces will rub together, generate excessive heat, cause abnormal wear and quickly become dull. When you have properly adjusted one end of the reel, go to the other end and repeat the procedure.

Keep adjusting the reel-no more than a few thousandths of an inch at a time and alternating between both ends of the reel-until the contact is uniform along the entire bedknife.

* Setting the cutting height Now that the reel to bedknife on-cut setting is correct, adjust the height-setting bar or gauge to the desired cutting height as determined by your turf type andmowing conditions (see photo, below).

You set the actual cutting height using the front roller. However, before you begin, make sure the rear roller is parallel to the bedknife.

The cutting unit's rear roller will have two screws on either end to adjust it to the height-setting bar. Begin by setting one end of the rear roller to the correct height. Adjust the screw at the other end of the roller assembly to ensure the pitch of the blade is less than the height of cut by 1/64 inch with 5mm bedknives and by 9/64 inch with 8mm bedknives.

The setting-bar screw adjustments must remain the same while adjusting the height of cut on each cutting unit on the mower. It is important that all cutting units be set at the same height of cut. Also, never re-adjust the screws after initially adjusting the setting bar. This may cause the cutting height to differ on each cutting unit.

After adjusting the rear roller to the setting bar, bring the front roller down toward the setting bar-using the micro-adjusters at each end of the front roller-to the desired height. Do this slowly to avoid over-tightening.

* Squaring the rear roller and bedknife To ensure consistency, repeat the following procedures on each of the mower's cutting units in exactly the same manner. Keep in mind that this is a gradual process and you prevent a lot of readjusting later by taking your time.

Make sure the front roller is raised enough so it does not touch the setting bar at the same time. After adjusting the setting bar, place it at one end of the cutting unit.

Adjust the rear-down roller so it: * Touches the rear of the setting bar. * The rear screw of the setting bar touches the heel of the bedknife (the trailing edge). * The front screw of the setting bar rests on top of the front edge of the bedknife. There must be contact at all three contact points. If not, repeat this process. When you have achieved the correct setting, tighten the adjusting nuts with your fingers.

Move the setting bar to the opposite end of the cutting unit and adjust the rear roller so: * It touches the rear of the setting bar. * The rear setting-bar screw touches the heel of the bedknife. * The front setting-bar screw rests on top of the cutting face of the bedknife. Tighten the adjusting nuts with your fingers.

Move the setting bar back to the other end of the cutting unit. Recheck to verify that the setting bar touches the cutting unit at all three points. Tighten the adjusting nuts. Repeat this step at the other end of the cutting unit.

After tightening the adjusting nuts, recheck each end with the setting bar to verify the adjustments have remained unchanged. The rear roller should now be parallel with the cutting face (see top photo, page 34).

Some final thoughts If you haven't adjusted the cutting height correctly, you'll ultimately see it in the quality of cut and the finish because your turf will have a slightly different color and texture. Likewise, if the front and rear rollers are not parallel to the bedknife or each other, you will end up with a "step" finish caused by the roller-height differences.

Ideally, you must inspect the cutting height each time the mower comes back from the course and (if needed) make proper adjustments at that time.

Sure-fire adjustment pointers * Do not place your hands or feet near spinning reels. Allow the reels to come to a complete stop before working on them. * Turn the engine off before adjusting the cutting height. * Adjust the rear roller parallel to the bedknife. * To set the "on-cut" cutting action, lower both sides of the reel evenly when adjusting the reel to the bedknife (no more than a few thousandths on the micro-adjusters at one time for each end). * Using paper or a business card, always test the cut after adjusting the reel toward the bedknife. * After the adjustment is completed, the reel should revolve freely. Excessive tightening of the reel against the bedknife causes premature wear and damage to the cutting faces. This will also cause undue stress on the cutting unit's drive system. * Too little contact between the reel and the bedknife causes the blades to dull quickly, which results in torn (not cut) turf and fewer clippings. * Monitor height of cut and reel adjustment during operation to ensure an even cut. * Do not turn reels by hand. Reels and bedknifes are sharp and could cause severe injury. Make sure you wear gloves and turn the reels using a block of wood.

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