0 Mower blades - the sum of all parts

In this article, Reesink Turfcare's Clive Pinnock, who has been in the industry for over thirty-two years and is the first in the turfcare sector to achieve a level four in the Landbased Technician Accreditation scheme (LTA), one of the highest training accolades there is, talks blades. Specifically, how these unassuming pieces of metal can mean the difference between frayed and unhealthy grass, or the immaculately clean, healthy cut your turf needs


Too often, we talk about how important it is to have a good quality mower and it's very easy to forget that, just as important as the mower, are the parts you put in it. With so many options for cylinders, with five, six, seven, eight, ten, eleven and fourteen blades, what's best for which turf tasks?

The number refers to the number of the actual blades in the cylinder, and the lower the number of blades, the higher and rougher the cut. So, for example, grounds mowers - which we at Reesink refer to as the machines used by local authorities and landscape contractors - are generally five and six blade machines. These cylinders can chomp through taller, coarser grass typically found in parks and on the verge-side.

Meanwhile, for that ultra fine finish required on golf course greens the eight, eleven and fourteen blades will deliver the smooth and consistent finish players demand. The tees and fairways and many sports pitches, which need a healthy cut, but do not require such a fine finish, the five and seven blade cylinders are perfect.

Blade by design

Perhaps not often taken into account is the design of the blades. It is expected that blades should be designed to fit the cutting unit whatever the cutting unit width and, of course, as with all things, some do this better than others and this should be taken into account when choosing the blades for your machine. Choosing blades produced by the manufacturer of your machine is recommended. Toro parts, for example, will give the best fit and help get optimal performance out of your mower. Choosing a generic blade that is not precisely manufactured for the mower may result in poor quality of cut due to incorrect blade angle and height.

But it's not just the fit to consider, there are also the design capabilities too, which ensure that the blade is designed, or one could say crafted, to better serve the turf's needs. I know Toro has spent extensive R&D time looking at how blades with sharpened cutting edges at both ends and a sail area that is curved up to create airflow, produce a better quality of cut. Depending on the purpose of your mower and the design of the cutting unit, the blade sail will adjust to create more powerful airflows. These varying airflows will whip the grass blades upright to expose them to the cutting edge of the blade, then send the cut grass out of the discharge.

Fig.1 (A-D left to right) illustrates the design differences of blade sails. Blade A shows a low sail, also known as a flat blade. The benefits of this design are low noise levels, lower power consumption and reduced discharge velocity of clippings.

Blade B illustrates a medium sail with a medium flow for a better quality of cut and better overall performance in most conditions. The high sail, blade C, provides the better airflow, best quality of cut in most grass conditions and is the preferred blade for bagging applications.

Meanwhile the atomic sail, blade D, has an aggressive teeth design for shredding grass, leaving behind a fine mulch.

Blade inspection, best practices

Whichever blade you opt for, best practice applies to all. All blades must be checked to ensure they are not twisted or bent as they require more horsepower to operate, damage the turf, create vibration and noise and shorten spindle life.

Regularly and carefully examine the cutting ends of the blade, especially where the flat and sail parts of the blade meet. For safety, it's extremely important to replace the blade when you notice wear. Eventually, a piece of the sail may break off and be thrown from under the deck housing, possibly resulting in serious injury to yourself or a bystander.

Make sure the blade isn't bent up at the ends. If the centre of the blade is lower than the blade's cutting edge, it may result in damage to the tips of the grass blades.

Mowing with the wrong or just blunt blades can cause grass tip dieback, a condition that turns the leaf of the plant brown and puts it at risk of disease. Look for blades with a toughened steel microstructure to improve wear resistance.

Upward spiral for cylinder technology

Cylinder design and technology has made huge leaps in the last few years. The new double A-arm suspension system, for example, utilises flex technology in conjunction with DPA cutting units which keeps the cutting units parallel to the ground to make gouging, scalping and scrubbing of the turf a thing of the past.

A lift-in-turn feature provides a slight lift to the inside of each cutting unit during turns for a consistently level cut. This feature eliminates the dreaded triplex 'ring', step cutting and unsightly variations on the clean-up pass for improved playability and aesthetics.

An all-electric reel drive system eliminates hydraulic leaks associated with past cylinders, whilst powerful 1.5hp electric motors are also sized for up to 3hp at peak load to handle the most challenging cutting and verticutting applications. They also provide the power needed to support slight cylinder-to-bottom blade contact for optimum cutting. Toro uses a 'shin system' to ensure the space between the cylinder and bedknife is parallel. The magic number here is 0.0002.

Despite all these advances though, you sometimes need to get the trusty pedestrian mower out. Pedestrian mowers hold a special place in a turf manager's heart, for the simple reason that, with a pedestrian mower, man and machine come together in a way that just isn't possible with a ride-on. They lock-in control at an intricate grass roots level and give credence to the saying 'the best things come in small packages'.

Pedestrian mowers can be relied upon to always deliver that unrivalled, perfect finish and are most often relied upon when ground conditions are bad or there is an event, such as a tournament, when only the best will do.

Resting cylinders on hard surfaces

You need to be careful when resting machines on hard surfaces as it can put units off cut. Due diligence should also be taken when it comes to set up and wherever you put the unit down, as it is very easy to disturb the cutting configuration.

Sharpening

To determine whether your mower cylinder needs regrinding or a replacing, put it to the paper test. Wearing the correct safety attire, carefully hold a piece of paper at 90 degrees between the cylinder and the bottom blade and slowly turn the cylinder by hand to see if they are cutting correctly. If this results in anything less than a precise clean-cut piece, the cylinder may need regrinding or replacing. It is also possible to check the service life of a cylinder by measuring the diameter to see if it is still within the specification prescribed by the manufacturer.

For all blades, we recommend spin and relief grind, as is also Toro's preferred method. Light contact is important to keep the units in factory condition.

Grinding and cutting technology in a wider sense, in fact, is such a big subject that Reesink has dedicated a course to the subject. The course called 'Cutting Technology and After-cut Appearance' is a good introduction to troubleshooting, routine servicing and maintenance of cutting units. It's delivered in partnership with Bernhard Grinders, covering agronomy principles with factors that affect clip rate, unit configuration and after-cut appearance and grinding procedures. It's certainly a course worth considering for landscape contractors, greenkeepers and local authorities with responsibility to ensure a smooth running fleet.


Cylinder mowing has come a long way!

Cylinder mowing has come a long way since 1919 when the 'Toro Standard Golf Machine' replaced horse-drawn cutting equipment for mowing golf course grass. Revolutionary and innovative, this cylinder mower, in effect, launched the mechanical cylinder mowing era.

Since those long-ago days that saw five cutting units mounted onto the front of a farm tractor, the face of cylinder mowing now looks vastly different. And, whilst the standard of innovation and product development remains as ground-breaking, the technology is where the real differences are.

According to agronomists, cylinder mowing (reel mowing, as our American counterparts refer to it) is better for the grass being a more clean cut rather than torn, as experienced with rotary mowers. This is due to the blades spinning vertically (north to south) and creating a scissoring action against the bottom blade to cut the grass leaves.

There have been many note-worthy technological developments and advances since 1919; the list is long, but probably none more important than the recent arrival of the hybrid, which couples the quality of cut of the cylinder mower and adds to it the enormous benefit of an all-electric reel drive system.

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