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Michael He
Michael He
Graeme MacNiven
Graeme MacNiven

An Introduction & Guide to Grinding, with testimonials from the experts.

Posted on February 21, 2014 at 10:10 PM

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What is grinding? Do we need it?

How can blade sharpness affect the health of turf?

How can a clean cut protect turf from disease and minimise loss of moisture from the plant?

How does a clean cut improve ball roll and consistency of play?

How can such a simple thing make such a big difference?

 

Michael He lives and works in China and has worked on several European Tour Events around Asia for the last 4 years. In just the last year alone Michael has been involved with tournament support for all major tournaments throughout China, including the HSBC Champions, BMW Master and Volvo China Open.

Michael’s knowledge and expertise is second to none and he is a well-known figure around the golfing industry in China. Michael explains the basics of how and why we grind, “Any agronomist or Master Greenkeeper will tell you that a sharp blade cuts cleaner. In fact you don’t have to be an agronomist to know that. We have all used a blunt knife at some time or another, and we know how it hacks and tears at whatever we are cutting, be it bread, hair or grass.

The simple fact is a clean cut is just that. Clean. Surgically sharp mower blades slice cleanly through grass blades, severing the tissue cleanly and with minimal damage. Because all the grass blades are the same height and uniform in their appearance, the overall definition of the turf is improved and the ball roll is smoother, more consistent and often faster.

To understand the process of how a grinder works we need to look at the two different components of the cutting unit: the bedknife and the reel.

The bedknife

The bedknife is the most important part of any cutting unit and although it looks simple, is actually a very complex piece of steel. When you have your hair cut (if you still have any!) the hairdresser doesn’t just take the scissors and cut randomly away at your hair. What they do is use one hand to hold on to the hair, at equal height and present the hair into the scissors. The bedknife in a cutting unit is the hairdresser’s hand. It gathers the grass and holds it in to position until the reel blade comes around to cut the grass evenly.

The bedknife is not just a flat piece of steel that needs to be sharp to cut grass. In fact, the bedknife is only sharp as a by-product of why you actually grind it. The main reason for grinding a bedknife, is to create, or maintain two angled faces on it, which make the difference as to whether the grass is cut or not.

The first of these, the “top face” angle is ground, as its name suggests, on the top of the bedknife. It is a negative angle that slopes backwards, away from the actual point of cut on the unit. This is ground to allow the grass to eject away from the point of cut and clear from the grass coming into the mower. The degree of angle required varies, depending on the size and condition of the grass being cut.

Obviously the clippings from a golf green are tiny and only require a very small angle. Once this angle becomes worn and therefore creates a narrower gap, the grass isn’t ejected correctly and hangs around the cutting area, clogging the point of cut and therefore not allowing the incoming grass to be cut cleanly and leaving a bad finish.

This is the point at which the untrained operator would “tighten” the cutting unit down, bringing the reel and bedknife closer together to try and improve the cut. What they are actually doing is wearing the bedknife angle even more, closing the ejection gap even more and making the whole process worse.

The second angle, is known as the front face angle. If the bedknife is the most important part of the mower, then the front face is the most important part of the bedknife, so good maintenance of this is critical.

The front face is simply a ground level even face on the front of the bedknife. It’s there simply to push the grass up evenly and stand it up in front of the reel blades as the cutting unit moves forward. This is the “hairdressers hand”.

The front face needs to be flat and even. If the face becomes worn or rounded, which it will do over time because grass and especially top-dressing are very abrasive, then grass which is designed to grow horizontally rather than vertically such as creeping bentgrass, will not be presented evenly toward the cutting blades of the reel.

It is essential that this front face is maintained so it can carry out its job correctly. This can be done with a file, a facing tool or with a precision grinder while renewing the angle on the top face.

The cylinder

Often overlooked are the reasons we spin grind the reel. Yes it is to make each blade sharp, but it is also to make it cylindrical and even. There is no point having all the blades sharp, if only every third blade cuts because they are not of even height.

The Importance of an even reel.

We are often asked, when do you know a reel is finished grinding? The answer is not when it’s sharp, but when it’s even. A reel that is maintained and ground more regularly is going to be easier and quicker to grind than one that is only ground once a year because it is going to be more even. The actual sharpening of a blade only takes seconds.

Sharpening is an essential process that has to be done regularly in order to guarantee the players and customers who judge the course the playability they demand today so these machines have to be very simple to use and fast and accurate in order to deliver such high standards and save the course money.

Let’s look at what happens if you cut grass with blades that are not sharp enough?

Your cutting machine will tear at the grass leaving uneven and poorly cut blade tips. These ripped and ragged blades of grass will bleed, losing plant moisture and nutrient. Also leaving the tips open and vulnerable to disease from spores such as Fusarium and other leaf-spot diseases.

The moisture lost through damaged tips has to be replaced. Repairing and regenerating plant health requires accelerated growth and that means a greater demand for food, which often means more fertiliser and water too. Both these are very costly to supply and to deliver.

So – you want sharp blades? How do you find the budget to buy grinders? Which grinders should you buy and what should you look for?
“I don’t have the budget.” Is the cry we hear constantly, but sharpening need not cost the course money. Like all budgets, you have to weigh up what you can and cannot live without, balanced by the savings you can make to your annual maintenance budget and the responsibility you have to sustainable management.

Savings come from two main areas – agronomic and mechanical

Agronomically speaking, clearly a reduction in the use of water, fertiliser, fungicide and top dressing can be a massive gain for the club. Not only are these expensive consumables reduced but also the labour costs of handling the materials, electricity to pump the water and places to store the chemicals – can all be dramatically reduced.

Mechanically, trials at several training colleges have demonstrated fuel consumption reductions of between 17% - 21 % - massive in today’s competitive climate.

Translate fuel reduction into mower life, engine wear, fewer parts to be replaced and so on – and it soon becomes clear that the benefits are very attractive to the bottom line profits of the course. Also, of course, if you burn less fuel, you create fewer emissions.

Spin or relief?

Spin grinding puts the cutting edge on the leading (front) edge of the cylinder blade and makes the reel cylindrical and even.

Relief from friction between the bedknife and cylinder is also essential. A "no-contact" set up gives relief from this friction, whereas a relief grind (or "blade thinning") removes metal from the back of the cylinder blade so there is less metal to come into contact with the bedknife, also reducing friction.”

 

So now you know the facts and figures, let’s hear from Graeme MacNivenDeputy Director of Agronomy, European Tour on how all this benefits the top end of golf.

This is Graeme’s 20th season – so he has worked on a lot of European Tours.

“I suppose the expectations are almost greater each year, always trying to do a better job. I work with so many people from different cultures with different expectations; sometimes it is a juggling act.

Bernhard have helped and supported us on many individual tournaments including The China Open BMW Masters in Shanghai, the HSBC Champions Tournament, also in Shanghai, The Volvo China Open, Binhair Lake, Tianjin.

The support we get from Michael is crucial with regards to ball roll and green speed, as well as the health of the turf.

We always keep an eye on how the clubs are preparing and if we know that Michael is on board, we then know that he has all the mechanics grinding correctly. Working with Bernhard means that we are more confident and have utter peace of mind that the job will be done professionally. That also frees us up to do other jobs – so it is invaluable.”

Graeme, originally from the Western Isles started his greenkeeping career at a links course in West Scotland. At the age of 15 his family moved to Surrey where he got the job as Assistant Greenkeeper at Sunningdale. From there he moved to Munich in 1980 and spent 25 years in Germany working for the BMW National Open. After 22 years he moved to Majorca and is now based in Palma. His job takes him overseas a lot, he reckons 60% of his time, but he still enjoys his job enormously.

“We have 5 people in our Agronomy Department and we support each other throughout the year, servicing Tournaments from start to finish. We go to each venue one week before the start of the Tournament. Everything needs to be in place by the Monday of the event for practice. There is always a lot of pressure to get it ready and then of course, pressure to keep it consistent and present the same quality each day.

The players are very demanding and quite rightly expect everything to be in place and working perfectly for them. I think standards have improved generally over the years and it’s the whole team that makes that sustainable.

With the resources we have we are fortunate to be able to call in extra people, support and machinery.”

Graeme is very used to working with different cultures but he says, “I’m constantly surprised that despite all the cultural differences between Greenkeepers across the World, they do things the same way. Whether they are in Sweden, South Africa, USA or China, the way a reel is sharpened or the way the greens are cut or the required standards and expectations are all universal and I find that quite comforting.”