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Old 03-15-2010, 11:10 PM
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txgrassguy txgrassguy is offline
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Alright, Jason - there is simply no good way to maintain a reel mower that has bedknife to bed bar contact. Regardless of the type of turf mown, C3 or C4, in order to prevent rifling, a gap has to be maintained between the reel and bed knife.
Green, you are confusing what a relief verse spin grind consists.
On a correct grind, a reel is ground into a true cylinder shape which results in the trailing edge of the reel needing that edge "relieved". Hence the name "relief" grind - all the reel technician is doing is relieving the trailing edge.
The "spin" comes to play as most grinders, particularly those made after the early 1980's, drive or "spin" the reel to achieve the cylindrical grind through the use of a dedicated drive motor on the grinder.
For instance my Neary grinder has three motors: 1 to grind, 2 to transverse the grinding head and 3 to spin the reel. See, a "spin" grind.
Most newer grinding machines have 4 motors, the first three as described and the forth automatically feeds the grinding head into the reel. On mine I have to listen to the grinder "spark out" before manually feeding the grinding head into the spinning reel.
The relief becomes important at lower heights of cut, namely 0.150" and below, where the lower height requires a smaller gap between the reel and bed knife necessitating the trailing edge to be relieved in order to acquire the correct gap without reel to bed knife contact.
What you guys are confusing is prior to spin grinding, all grinding was done with a hand fed grinding motor mounted on the grinder. Because your left hand controlled the intake of each individual blade of a reel, you first hand to number all of the blades because you initially fed the grinding wheel back and forth across each blade before advancing to the next blade until you reached the last numbered blade of the reel.
Then you would advance or close the distance of the grinding head and start grinding in reverse order - that way the idea was all blades of the reel assembly were ground more or less the same. However, as heights of cut became lower the discrepancies in grinding accuracy became a problem as a technician couldn't adjust the concentric bolt the bed knife assembly pivots on to make up for the errors.
Which is why spin grinding was developed.
What you guys get when your reel mowers are spin ground is a more accurate, controlled distance between the reel and bed knife and the reason back lapping (which is the process of applying a water soluble paste to the reel and bed knife) doesn't work is the relief aspect of the spin grind isn't what is out of whack.
What has become dull is the edge of the bed knife itself - THIS is where you first need to address when correcting the quality of cut.
Depending upon how good you are with a powered grinder, you need to "face" the bed knife, THEN back lap as just back lapping won't return the bed knife to the proper relationship to the reel.
For those crappy Eastman, Tru-cut, essentially all home owner grade reel mowers where the bed bar assembly becomes a stressed part of the reel assembly frame, you MUST have some manner to "face" the bed knife as part of the maintenance process.
Go to R&R products for a hand held facing grinder. Start with this first then once you have acquired the feel for facing you can up-grade to a powered facing grinder.
Then back lap the reel to bed knife, wash the reel, blow dry then check with a piece of manila file folder material the cut across the ENTIRE bed knife face. Make whatever adjustments necessary which first results in a uniform cut while not having ANY contact with the reel to bed knife.
Beginning to get the picture now about the differences in grinding techniques effect set-up?
To avoid the constant headaches associated with spin ground reels, request that the entire grind be a relief grind. If you really want to give the technician hemorrhoids, demand the entire reel be first spin ground, THEN demand the entire reel have a complete relief ground into it.
I'll warn you though, be prepared to either pay double for the grinding or to dodge a reel assembly thrown at you.
Yes you'll loose more life on the reel assembly with a complete and true relief grind but until you acquire the feel necessary to maintain a spin ground reel assembly you will be fighting a constantly changing gap - and without a face grinder you are **** out of luck to properly correct in the field. Particularly when you consider your mowers are bouncing from one site to the next and this alone will whack the willy bejesus out of the reel to bed knife gap.
You have to remember, a true spin grind results in a much closer gap in a much more uniform manner (if properly set-up which almost never occurs unless the guy doing the grinding is careful). One minor thump, one bump, one moment of inattention and you have lost that small gap which usually results in either a stringing cut or suddenly the machine is making that scissoring sound, cuts great for a moment or so which is usually preceded by a tortured metal on metal sound as the reel and bed knife eat themselves from the heat generated from the contact - which is known as rifling.

Now that I have crossed everyone's eyes and wives are running in to determine that source of the "thump" your heads caused by hitting the table, I'll say this:
At heights of cut from 1/2" to 2", a properly sharpened Harrier mower will be essentially indistinguishable from a reel mower, is orders of magnitude easier to maintain, is less costly to maintain and is almost always much faster to operate.

As one final point, my experience grinding reels stems from over twenty years in the turf industry utilizing reel mowers on golf courses both C3 and C4 turf, through my time at Augusta National to running my own operation. I can and do operate reel mowers as a part of my business but that's because I know what I am doing - plus drinking a whole lot of beer with the Jacobsen/Ransomes reps while in Georgia.
Hey, if you guys want to run reel mowers go for it - it's no skin off my ass. But be prepared to shell out some money to acquire the skill necessary to maintain reel assemblies unless you know of a good reel technician at a local golf course who will take you by the hand to demonstrate what I just typed.
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