Reel Sharpening Of Reel Mower
Jul 12, 2023
Sharpening is an essential aspect of maintaining the cutting efficiency of a reel mower. How can you discern the need for sharpening? Look for indicators such as an uneven grass cut, a lackluster appearance with brown-tipped blades, streaks, stragglers, and excessive noise emanating from the cutting unit.
One reliable method to determine this is by inspecting the edges of the reel and bedknife. Examine them for signs of dullness, nicks, bends, or improper contact between the two components.
The consequence of wear: the leading edges become rounded, and the bedknife's angle conforms to the circular path of the blades.
Visually inspect the reel blades and bedknife for any damage, and gently run your fingertips along their edges. However, exercise caution by ensuring that the reel is not operational, and avoid sliding your fingers along the length of the edges.
Rounded edges on the reel blades and bedknife will cause the grass blades to be crushed and torn rather than precisely sliced. Neglecting to maintain proper contact will quickly result in dulled edges.
When the bedknife and reel maintain light contact, a clean cut is achieved, resulting in an enduring sharpness.
Insufficient contact, indicated by a gap between the bedknife and reel blade, accelerates wear on the cutting edges and necessitates more frequent grinding.
Lack of contact leads to the undesirable pinching and tearing of the grass leaves, compromising the quality of the cut and hastening the deterioration of the cutting edges. As a consequence, the aftercut appearance suffers, and the health of the turf is adversely affected.
It is crucial to keep the cutting units as keen as possible, as it offers a multitude of benefits:• Fosters the growth of healthy grass.• Maximizes the cutting unit's performance.• Prolongs the mower's lifespan.• Optimizes the operator's mowing time.• Enhances the tractor's operational efficiency.• Ensures the best possible aftercut appearance for the turf.
When the blades of the cutting unit become dull and the quality of the cut deteriorates, the natural inclination is to tighten the contact between the bedknife and reel, resulting in heavy contact.
Excessive bedknife-to-reel contact can lead to rifling, characterized by grooved or wavy wear patterns on the reel and/or bedknife. This condition can only be rectified through grinding of the reel and bedknife. BACKLAPPING WILL NOT CORRECT THIS CONDITION. the bedknife will need to be replaced rather than simply ground.
A barrel-shaped reel, caused by flexing of the cutting unit frame, will also require grinding to restore it to its cylindrical shape. This issue is more likely to occur in cutting units with welded frames, rather than the newer DPA model cutting units with sturdier bolted frames.
Flexing of the frame can result in uneven wear and eventually lead to rifling.
If the reel wears unevenly, it becomes challenging to maintain parallel alignment of the bedknife across the entire width of the reel. You may be able to pinch paper in the middle, but not at the ends, or vice versa. When adjusting a cutting unit with this condition, the tendency is to tighten the bedknife-to-reel contact so that the paper can be pinched and cut across the entire bedknife and reel, resulting in heavy contact.
Grinding is also necessary if the reel becomes cone-shaped or tapered. Reels naturally acquire a tapered shape with use. Failure to grind the reel back to a cylindrical shape can lead to a discrepancy in the cutting height between adjacent cutting units.
There are various methods for sharpening a cutting unit, and the choice of method depends on the condition of the cutting unit and the intended use. For instance, if you are about to mow greens that have undergone core aeration or topdressing, grinding the reels and installing new bed knives may not be ideal.
Sharpening Methods:
• Maintain proper ADJUSTMENT
• BACKLAP the bedknife and reel
• GRIND the reel and bedknife
By regularly backlapping, the sharpness of the reel blades and bedknife can be maintained for longer periods between grindings.
However, it's important to note that backlapping cannot be used to sharpen a dull reel or bedknife. Backlapping serves as a maintenance practice for maintaining the edge.
During backlapping, as the reel blades run against the bedknife, a slight burr may form along the front cutting edge surface of the bedknife. Use a file or facing grinder to remove this burr.
Backlapping should be performed after a single blade grinding to establish a land area and ensure a perfect match between the bedknife and reel edge.
Backlapping is not intended to correct severely damaged or rounded blades, rifling, or taper. If, after approximately 5 minutes of lapping, the edge is not restored, it is time to grind the reel and bedknife.
Backlapping is often a scheduled maintenance process, particularly for greens mowers.
WARNING:
Ensure the utilization of a brush endowed with an elongated handle to apply the polishing compound onto the rotating reel. Employing a brush with a short handle could potentially result in your hand being entrapped within the reel, thereby causing severe harm. Exercise caution by keeping your hands, feet, and attire at a safe distance from the moving components!
Should you choose to incorporate backlapping into your usual maintenance routine, engage in backlapping sessions frequently, albeit for brief periods of time. For instance, allocate a mere five minutes per cutting unit.
Prior to commencing the appropriate grinding of the reel, rigorous cleansing and inspection of the reel are prerequisites. Verify that the blades are securely affixed and unmarred. Furthermore, ascertain the reel bearings' optimal condition, free from any discernible play. Confirm the alignment of both the cutting unit frame and roller brackets, ensuring neither distortion nor impairment resulting from encounters with trees, posts, or the edges of cart paths. Align the cutting unit itself so that the grinding wheel moves in parallel with the reel shaft, thus achieving the desired cylindrical form during the grinding procedure.
Adhere strictly to the guidelines provided by the manufacturer of the grinder for the setup and operation of said apparatus.
During the grinding process, judiciously avoid overheating the reel blades. Gradually extract minute amounts of material with each passage of the grinder.
Upon completing the grinding process, meticulously undertake a comprehensive setup and adjustment protocol for each cutting unit.
Reel grinders are produced by various manufacturers, many of whom also fabricate bedknife grinders.
Never neglect the essential precaution of wearing a face shield or protective eyewear when partaking in grinding or backlapping activities.
It is of utmost importance to comprehend that reel mowers have been meticulously crafted and engineered to maximize the utilization of available power derived from the engine and hydraulic systems. To achieve this goal, we incorporate a "relief" or back grind on each reel blade, effectively reducing the surface area of contact between the blade and the bedknife. This proven approach not only diminishes power requirements but also enhances the overall operational efficiency of the machine. The significance of this aspect varies depending on factors such as the terrain, grass type, and quantity to be cut.
There exist two distinct methods for manufacturing reel blades with relief. These blades are fabricated using straight stock steel and are subsequently either ground (utilizing a taper relief) or milled (employing a scalloped relief). Regardless of the chosen technique, a relief is incorporated during the manufacturing process. Additionally, on milled relief blades, a finely ground relief is diligently applied.
When it comes to grinding reels, one method employed is Spin Grinding, also known as Flat Grinding. In this process, both the reel and the grinding stone rotate concurrently, ensuring the precise sharpening of the reel. It is occasionally asserted that backlapping is unnecessary following spin grinding since the reel attains a flawless cylindrical shape upon completion of the grinding process. However, this outcome depends on the correct alignment of the reel in the grinder prior to sharpening. Furthermore, the bedknife and bedbar must maintain perfect straightness and parallelism to the reel upon mounting. Performing backlapping aids in removing burrs and rough edges, resulting in a honed edge that promotes even grass cutting.
Should one choose to employ a spin grinder to sharpen straight stock reel blades, such as those found on fairway mowers, a portion or all of the relief may be inadvertently ground off. To restore the relief that was originally manufactured on the blades, the alternative grinding method (single blade relief grinding) must be utilized. It is recommended to conduct the relief grinding first, followed by spin grinding to reestablish the cylindrical shape of the reel and determine the appropriate land width.
Another method employed is Single Blade Grinding, also known as Relief Grinding or Back Grinding. Modern grinding equipment allows for both spin (or flat) grinding and single blade grinding to be performed using the same machine. Single blade grinding is employed when necessary to restore the relief or back grind, which is subsequently followed by spin grinding to sharpen the reel and restore its cylindrical shape.
A recommended relief angle of 30 degrees for each reel blade is advocated. It is permissible to deviate the relief angle by up to 5 degrees in either direction. Opting for a larger relief angle reduces the frequency of reel grinding since the blade land width wears at a slower pace. Nevertheless, a larger relief angle renders the reel blades more susceptible to damage caused by impacts. Conversely, a smaller relief angle may necessitate more frequent reel grinding to uphold the desired blade land width but enhances resistance to damage from impacts.
Prior to commencing the grinding process, ensure that all components of the cutting unit are in optimal condition. Faulty cutting unit components, depending on the type of grinder used, can have an adverse impact on grinding outcomes. Verify that the reel bearings are in good working order and properly adjusted before grinding. Inspect the cutting unit frame and roller brackets to ensure their trueness and absence of bending or damage.
It is essential to identify the specific type of reel to ensure accurate grinding procedures. There are four distinct reel types utilized in various products, categorized by the type of blade relief (scalloped or tapered) and the arrangement of the blades (radial or forward swept). It should be noted that Greensmaster machines solely employ scalloped forward swept reels.
Follow the instructions provided by the reel grinder manufacturer precisely to achieve grinding results in accordance with specifications.
During the grinding process, exercise caution to prevent overheating of the cutting reel blades. Remove small increments of material with each pass of the grinder. Conduct relief grinding on the reel blades until the blade land width reaches the minimum threshold if the current land width exceeds the designated service limit. Subsequently, perform spin grinding to restore the cylindrical shape of the reel and establish the specified blade land width following relief grinding.
Upon completing the grinding of the reel and/or bedknife, adjust the cutting unit as instructed in the Cutting Unit Operator's Manual. After cutting two fairways, reassess the contact between the reel and the bedknife. This initial use will facilitate the removal of any burrs from the reel and bedknife that may cause improper clearance, subsequently accelerating wear. Regularly reassessing the reel to bedknife contact after grinding will prolong the sharpness of both the reel's edge and the bedknife.
Regardless of the grinder utilized, be sure to compensate for any cone or barrel-shaped irregularities. Grind parallel to the reel shaft and refrain from establishing the grinder's setup solely based on equalizing spark patterns at each end. This approach fails to rectify the slight cone shape that often manifests in worn reels.
Reels naturally encounter greater wear on one end compared to the other. Therefore, verify that the reel centerline, represented by the reel.
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