Cylinder grinding Pitchcare Classifieds
Maximise workshop efficiency by relief grinding your cutting units
A huge amount of research and development has gone into designing a cutting unit to produce the cleanest cut possible with the least amount of fraying and tissue damage to the plant. The result is that all manufacturers of grass cutting equipment supply new units with relief ground edges.
Why relief grind?
Tests carried out by leading manufacturers have established that relief ground cylinders stay on cut up to three times longer than spun ground ones and require less horse power to drive the unit, resulting in greater fuel efficiency and less stress on the hydraulic power systems. In addition, a relief ground cylinder will withstand the abrasive effects of topdressing far better than one spun ground because the relief edge on both the bed‐ knife and the cylinder allows the topdressing to clear the cutting blades easily, helping to prevent the dulling effect seen on spun only units.
Ian Robson, ProSport UK Ltd., the UK & Ireland Importer/Distributor for Foley United & Neary Technologies, explains why relief grinding maximises the performance of reels by giving a factory finish every time
Horse Power Study
As a reel wears flat and loses shape (becomes coned), more stress and strain is put on the cutting systems.
A vital question for a workshop manager is how to maximise efficiency and minimise labour and maintenance equipment costs. One area to achieve excellent savings is to look at how you maintain the sharpness of your cutting units.
Firstly, why is having sharp cylinders (reels) that are the correct shape so important anyway? The answer is obvious ‐ unhealthy turf brings a whole host of other issues which are costly to correct. Therefore, prevention is a far more economic approach than a cure.
Continual relief grinding also decreases the squeezing and tearing of the grass as the units get dull and, most importantly, it allows the cylinder to be returned to a factory specification perfect cylinder as quickly as possible.
The overall cleaner cut achieved by relief grinding gives a better after‐cut appearance, increased recovery rate due to the clean cut of the grass and reduces the stress on components because less horsepower is needed to drive the cylinder.
www.prosportukltd.com Tel: 07779 270501
Typically, when a new mower is delivered, the reels will be a perfect cylindrical shape. Over time, the blade naturally loses shape, and the sharp edge it arrives with becomes flat and dull, often meaning the reel is no longer a perfect cylinder from end to end. This is referred to as ‘coning’ and a natural point for grinding to take place.
Fig 1: New cylinder with perfect relief ground cutting edge
Fig 2: Used and dulled edge following wear over time
Fig 3: Flat and dulled edge. All shape is lost. The sharp edge and relief is gone
Using the figures from the above study, a 5‐gang cutting unit with relief can require up to 4.5hp (5 x 0.88hp = 4.5hp) to drive the cutting units, therefore a 35hp engine has 30.5hp remaining to drive the rest of the traction system. A 5‐gang unit which has been spun ground only, can require up to 13hp (5 x 2.59hp = 13hp) leaving only 22hp to drive the rest of the traction system.
So, it has been established that relief grinding your cutting units saves you money not only by reducing workshop maintenance time with far fewer grinds but also through a reduction in fuel costs and replacement parts.
It is also important to acknowledge what relief grinding does for a reel. By removing metal from the trailing edge of the blade, it forms a relief angle, which reduces the contact area of the cutting edges, resulting in less friction, longer wear life.
134 I PC DECEMBER/JANUARY 2018
The decision then sits between touch‐up and spin grinding, or relief grinding. If there is sufficient relief still on the reel, then a quick touch‐up is fine but, once more than 50% of the relief has gone, my advice would be to relief grind again and remove any coning. Failure to remove the coning will eventually be seen in an uneven cut appearance of your turf.
Foley machines are set‐up for both choices, and some models, such as the ACCU‐Sharp, ACCU‐Pro and ACCU‐Master, have automatic grinding pre‐sets and adjustment systems to decrease time and labour.
But, the main question mentioned at the beginning comes back; how to get the most out of your workshop resources by choosing the most effective method to sharpen your cutting units. The answer is to trust the manufacturer’s judgement and return the reels as close to the original factory standard as possible and, for that, relief grinding is the best option. The bonus is this method also maximises performance and gives the best cut.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148
