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Straight Talk About Reel Sharpening
April/May 2000
Courtesy of Oakcreek Golf & Turf

If there's a lifeline in the turf industry, it could possibly be the reel mower. It was the reel mower that made it possible to develop and maintain hybrid grasses used to provide the modern golfer with a median on which he can fulfill his ever popular leisure sport.

It's the reel mower that provides a common link between golfer.... superintendent.... grounds person…. mechanic.... and equipment dealer.

The golfer doesn't care what extensive practices must be performed by the superintendent, he's happy as long as he's got a good lie or the balls roll true.

The superintendent doesn't care what the mechanic is faced with in providing him a tool to manicure his turf, he's happy as long as the equipment performs flawlessly.

But.... the poor old mechanic is expected to make "silk purses out of sow's ears!"

Mowers of today have the most sophisticated hydraulic systems, the most efficient engines, computer controls and gauges, all the features to keep the operator comfortable. Somehow "serviceable" was not a prerequisite.

In many ways the technology in today's equipment of the respective manufacturer's own service department. These deficiencies of the course filter down to the dealer's service department, then on to the repair shop at the golf course, or end user.

The recent emphasis and organizations of golf course mechanics is helping to satisfy these deficiencies. Some of the more active groups invite industry representatives in, to keep the members up to date on service tips and techniques. The sharing of experiences and ideas among the members at these meetings often accomplishes more that enough to be well worth the time, effort and expense.

We in the industry should rally to the support of the mechanics associations, assisting them in their desires to learn more and improve their stations in life.

We are regularly invited to participate in seminars at some of the associations around the country and share our experiences and knowledge of reel sharpening. We make every effort to accommodate any requests for our participation.

Through the years, we've found reel sharpening to be one of the most misunderstood and controversial topics facing the industry today. Analysing the evolution of reel sharpening provides a more clear understanding of the subject.

In the past, once a reel left the manufacturer, there was no provision to accurately resharpen it. the accepted practice was that of single blade grinding. This method would be time consuming and accuracy rests in the talent of the person operating the grinder. The idea was to regrind each blade until it had a sharp cutting edge. In as much as this produced a sharp blade, it did nothing to ensure the reel to be a true cylinder. Even though the grinder operator took great care in keeping the blades the same length, it was never done without the need to back lap to re-create the cylinder. The amount of back lapping required, depended on the meticulous care of the grinder operator. Back lapping would then be applied until each blade would effectively cut a piece of paper as efficiently as a pair of scissors. It was not uncommon for back lapping to last for hours. The art of sharpening a reel also included grinding an angle off the back of the blade as to maintain as thin as possible a reel blade that would produce less friction when adjusted to the bed knife to create a shearing or scissor cut. In North-America it is as a shear that most reel mowers are used as to produce crisp, clean cuts at low heights.

In Europe however, the reel mower because of it's tendency not to sling debris hazardously as a rotary or flail mower, would find it's place in mowing roadsides, verges and parks. Our British brethren often refer to a reel mower as nothing more than a rotating scythe. In this arrangement, speed, weight, and a sharp edge produces the cutting action. A bottom blade is added to enhance the action by supporting the grass as it's being cut. The reel is not required to slide across the bottom blade, thus, friction is not a concern. The quality of cut would be equivalent to that of a rotary or a flail.

Just as one would practice resharpening a rotary blade or a flail blade, all that would be required of a reel blade would be a sharp edge. it was this requirement that initiated the development of the spin grinder. The spin grinder proved to be an excellent device for producing a sharp edge to a reel blade. After sharpening a reel with a spin grinder, it would cut rather efficiently for a short period of time, producing a shear cut. This system works quite well as long as the reels are kept sharp by spin grinding regularly.

Since spin grinding produces an edge the full thickness of a reel blade, once the blades are slightly dull the pressure required to maintain a shear action with the bed knife will develop a considerable amount of friction. This friction will be enough to drastically affect the drive components of the reel mower. More power is required whether it's hydraulic, gear, or belt driven.

For two reasons this system totally replaces back lapping. First, the initial need to recreate the cylinder as with a single blade grinder is eliminated. Second, back lapping as a routine mid-season practice is replaced by a regular spin grinding to keep the blades sharp.

The best of both worlds is found in the practice of single blade grinding a relief angle off the back of a reel blade and then turning the reel to a perfect cylinder by lightly spin grinding. This method is used by all North-American reel manufacturers and is preferred as a maintenance practice by all O.E.M.'s.

This method also eliminates the need of the initial back lapping after grinding. By producing a relief angle, mid-season back lapping to maintain a sharp cutting edge can be enjoyed quite efficiently and effectively. Most all current production hydraulic driven reel mowers have a standard feature, a back lapping mode, by which all reel units on a multi-gang unit may be back lapped at one time.

When considering which method to adopt, several things should be considered:
a) the reel mower's application,
b) what is best to obtain optimum performance out of a reel mower,
c) manpower: can you designate one or two persons to regularly and routinely resharpen reels,
d) qualifications of manpower- is skilled personnel available for operating a grinder versus the simplicity of back lapping.

With all things considered, the decision should be based on preferences of the mechanics, for when all is said and done, they must be the ones to make it work.

Turf Line News April/May 2000

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