Earning his Spurs - Pitchcare

cones reels and can damage reel
bearings.
The time spent annually lapping
mowers vastly exceeds the time it takes to
face the bed-knife, with a facer or file
and in-situ spin-grind a reel properly.
Is it a scythe?
When you set a mower as a scythe the
reel becomes a gathering device,
bringing the grass crop to the bed-knife.
The bed-knife is the scythe’s cuttingedge.
Correctly sharpened and angled, it
allows it to present the grass crop for the
reel to pull in against the sharp front
cutting edge.
No contact is required between the reel
and bed-knife when setting as a scythe,
just sharp edges, particularly on the bedknife.
The spiralled helix shape of the
reel blades are designed to provide a
sideways action when drawing the grass
along the bed-knife. The bed-knife has
to be sharp at all times.
Scissors will cut, but a scythe cuts
cleaner. This is precisely why a surgeon
uses a single-blade scalpel (which is
drawn through the flesh) instead of
scissors.
When setting the mower as a scythe,
with zero reel to bed-knife contact, there
is no need for a blade thinning a relief,
100% relief is there all the time, so the
machine runs easier and with less energy
input, less fuel use, lower hydraulic
pressures and so on.
When using an easy to set, in-situ type
spin grinding method with the ability to
set up and sharpen quickly, you can
lightly renew the reel’s edges as needed,
face up the bed-knife and always keep
the “no contact” setting in minutes. This
is a scything cut.
To maintain a scything cut the bedknife
is the most important part. The
bed-knife has three functions:
1. Presentation - the front face edge
primarily stands the grass up and
presents it for the reel, at the right
height. It must be sharpened at the
correct angles.
2. It is a cutting edge, therefore, the bedknife
must always be sharp.
3. Ejection - the top face angle is for
ejecting the grass cuttings from the
cutting edge. This angle will vary
according to the mower’s intended
use, but the top face angle is never
112
smaller than the reel diameter.
Therefore a 5 inch diameter reel will
require a 5 degree top face minimum,
then add 2 or more degrees for the
grass crop on say a fairway cut. This
will vary in different growth
conditions.
Bedknives do all of the cutting when you
set up a mowing unit like a scythe, the
blade must be sharp and have the correct
angles on the top face and the front face.
Two thousandths of an inch gap
between reel and bed-knife is ideal in
Northern Europe, but will need to be
reduced by half on some exotic or desert
grass species.
It is important to maintain the sharp
edge on the front of the bed-knife, with a
facer or a good file, in order to cut
cleanly without bruising the grass. This
will also enhance the definition of stripes
on the green, thereby improving the
after cut appearance and keeping the
pace consistent on greens all day during
competitive play.
Experiences at Celtic Manor
We have eight Toro 5410 fairway mowers,
five were purchased in 2007 and three in
2008. We do not backlap in favour of
grinding because it’s quicker using our
spin grinders.
The 2007 machines have been
sharpened twice, the first time to see how
long it took two men to grind five
machines during the average work
period in peak season (7 hours). Using a
calculator it’s easy to see that:
7 hours = 420 minutes divided by 25
cutting units = 16.8 minutes per unit.
The time started from driving in the
first machine to driving out the last one.
This included removing the bed bar,
grinding the bed-knife on the top edge
and front face, adjusting the height of
cut post grinding, and greasing each unit
before refitting it to the machine.
The technicians carry out all bed-knife
to reel adjustments, we set-up all of our
units with no contact at all and the
quality of cut is first class.
During tournaments, we give every
pedestrian greens mower a very quick
spin each time they are used, this takes
around five minutes per machine and
includes a couple of passes with our
Rapid Facer to ‘freshen’ the bed-knife
front face, and make fine adjustments to
the height of cut.
This is a ‘belt and braces’ measure,
purely for tournaments, because of the
limited time for course set-up before the
first tee-offs, the mowers must go out in
“perfect” condition.
Some figures for you to consider;
From independent field trials we know
that, when running a five unit fairway
mower set with zero contact, the
hydraulic pressure will be around 900lbs,
causing minimum mechanical stress to
the machine.
Running the same mower set with light
contact, but with reels easily turning, the
hydraulic pressure will increase to
1800lbs. Because the reel and bed-knife
contact begins to act like a brake, as reels
get hotter and begin to expand slightly,
more heat or heavy contact will increase
the braking effect still further.
Due to this braking effect of running
reels with light contact, the mower’s fuel
consumption will increase by 25 to 30%,
the transmission oil and engine oil
temperatures will be raised, producing
extra stress on hydraulic hoses, motor
seals and reel bearings, the risk of oil
leaks will increase, reel and bed-knife
wear will be much higher and quality of
cut will deteriorate rapidly.
Professional hydraulic mowers have
built in safety relief systems (similar to 3
point tractor lifts), which will release
pressure when the hydraulic system
reaches about 3,000lbs. This means that
any heavy reel and bed-knife contact will
begin to open the safety valves and risk
causing the hydraulic safety system to
bleed off pressure and, so, reduce the
efficiency of the mowing unit or stall the
cutting units entirely.
Remember that the way you set-up,
maintain and use your equipment will
change the performance and useful life
of your mowing machines. It will also
effect your manufacturer’s reputation
and warranties.
Reducing the wear and tear on your
machinery, and always setting your
mowers with a perfect zero contact cut,
will enhance your own reputation and, by
providing consistent, high quality playing
surfaces, you will ensure that your
members and paying customers want to
return again and again.
Do your own ‘zero contact’ cutting trial
today. It may change your life.