Back lap reels
"Backlapping is easy. Just tip the reel back, slap on a little compound, plug her up in reverse and in a few minutes your dull old reel will cut just like brand new!"
If you've ever heard anything like this in your shop, you're probably in a lot of trouble. It's strike one, and strikes two and three cannot be far behind.
There's a right way to keep your greens mower reels in proper shape, and it involves nine basic steps: * Clean your reel * Inspect reel and bedknife * Grease reel bearings and rollers * Adjust reel for backlapping * Backlap reel * Clean reel * Adjust reel-to-bedknife and height of cut * Test greens mower on nursery or practice green * Clean mower
Clean it first It is difficult to keep a reel sharp if you do not keep it clean. Your reel must be clean before you work on it, while you work on it, and after you finish with it. A garden hose will do nicely. You won't see, hear or feel the things you should if the reel is full of debris.
Carefully inspect the reel and bedknife. Back the bedknife away from the reel so there is no metal-to-metal contact. Grasp the reel firmly and pull to the left and right and up and down. There should be no movement. If there is, it's time to repair the reel. Slowly spin the reel. There should be no rough or uneven feeling as the reel slowly turns.
After you are sure all is well with your reel, carefully run your finger across the entire top surface of the bedknife. What you cannot see, you may feel.
Then inspect the bottom of the bedknife. If there is grass "juice" built up on the bedknife bottom, your reel has been tearing the greens, not cutting them. If you do not remove sand, mud or other unwanted material from the bottom of the bedknife and it may alter your height of cut.
After inspecting the reel closely, grease the reel bearings and rollers with a good-quality high-impact water-resistant lubricant. Often, the new grease will squeeze out water. If you find any water, rethink your greasing schedule. You may need to grease more often.
If you replace more than two or three bearings a year due to water damage out of a dozen or so reels, try another product. Find one that works in your mowing conditions and stay with it.
Proper lubrication is key for any bearing, and a greens mower is no exception. Bearing failure in a greens mower can cost more than an ugly streak in your green that may take several days to disappear. Bearing failure in a greens mower may ruin a new reel and bedknife.
The newspaper test Adjusting the reel for backlapping is easy. Use a 1-inch-wide strip of newspaper for a gauge. Do not crank down on your reel until it touches the bed knife. Place the paper between the bedknife and one blade of the reel. Rotate the reel one blade at a time while carefully adjusting the bedknife down with the bedknife-to-reel adjustment screw until the paper makes a soft flapping noise.
When the paper sounds like "flap-flap-flap" as you turn the reel, you are close to where you want to be. Work both ends of the reel-first one side then the other. When the distance between the bedknife and reel are just right, there will be a slight drag on the paper that you can feel as you pull it out.
Do not get the reel tight enough to cut the paper. There isn't much surface to a greens mower bedknife, and for sure there isn't much metal on the cutting edge of a greens mower reel. What you are about to do is violently rub a grinding compound between the reel and bedknife. Your goal is to extend the working life of your reel and bedknife, not to wear them out. Take your time with this adjustment. If done properly, it will take no more than a minute or two to adjust each reel.
Backwards spin When you are satisfied the bedknife is parallel with the reel, hook up your lapping machine, and spin the reel in reverse. There should be no metal contact, and the reel should quietly spin. If all is well at this point, apply a small amount of grinding compound from right to left with a paint brush on a long handle. The grinding noise should be consistent all across the face of the reel.
Try using a 120-grit compound for sharpening greens mower reels. As the grinding noise subsides, do not automatically dip your brush in the compound bucket for more. Simply brush over again and again until you have actually used all the compound already there. If you do this properly, a small amount of grinding compound can go a long way.
Something to note: Because you are actually grinding metal, there will be a time when you may have to close the gap between the reel and bedknife to continue grinding. Before tightening the reel, stop the machine. (To save your fingers unplug the lapping machine.) Wipe off a small area of the reel blade and a small area of the bedknife.
If both are sharp, do not continue to grind metal away. If the reel and bedknife are not sharp, turn the lapping machine back on. As the reel is turning, adjust one end of the reel in a very specific small increment. You should hear the reel begin to grind again. Next, tighten the other end exactly the same amount. Always tighten in very small increments. The grinding sound should slightly increase.
Now apply more compound evenly across the face of the reel. Continue this process for about 15 minutes. If your greens mower is not sharp or at least close to being sharp in about 15 minutes, you may have to mill the bedknife on your lathe. If the sharpening process is working, as a last step apply a small amount of 180-grit compound to finish the backlapping job. This fine grit tends to polish both the bedknife and reel cutting surfaces.
Clean it again After you finish grinding, wash the reel thoroughly with a garden hose. Be careful not to leave any grinding compound in the reel. When the reel is turning in the cutting direction any residue of grinding compound tends to dull the reel quickly. While you are washing the reel, leave the backlapping machine running. You will hear some grinding as the grinding compound is washed between the reel and the bedknife; however, after the reel is cleaned the reel will turn freely with no metal to metal contact.
Now that you have a sharp, lubricated reel, adjust the height of cut and the bedknife-to-reel clearance. Height of cut is the greenskeepers' choice. Reel-to-bedknife clearance is the mechanic's job. Zero metal-to-metal contact between bedknife and reel is ideal. Try for "cut one, leave one." Put two strips of newspaper between the reel and bedknife and adjust the clearance so the reel cuts one paper and leaves the other. It is an art, and with some practice and patience it can work well for you.
Take the mower out for a spin, and run it across a practice green or nursery. Check the engine, drive train and operator controls, and observe the cut. When your mowers go out of the shop early the next morning, you will know they are in first-class condition.
The last thing to do is wash the mower off again. There is nothing worse than leaving a greens mower reel full of wet grass.
Remember, a dull greens mower is a superintendent's strike one. If you are tearing grass instead of cutting it, you're putting it under unnecessary stress. The plant will use its nutrients to try to heal itself instead of growing. Strikes two and three might be disease, water or drainage problems. Any one of these factors affect the quality of your greens. Two or more problems at the same time may deteriorate your greens so badly that they can't recover. Don't strike out: A dull greens mower need not happen in your shop.
John R. Holland is a mechanic with the Franklin County Country Club (West Frankfort, Ill.).
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