Grinding Tips & Tricks from Stephen Bernhard

After doing this for as long as he has, he should have a few tricks up his sleeves…

Looking after bedknives – how the correct angles and surgical sharpness can help you achieve a superior quality of cut.

In terms of reel cylinder mower maintenance, the bedknife often gets overlooked. Bedknives take a lot of abuse in the cutting process – they have cylinder blades smacking against them at a high velocity, they run over sand and turf, hit debris, and are dragged across various surfaces.

However, spending a little more time and attention on your bedknives could reap serious benefits for your facility in terms of quality of cut and replacement parts.

Regular bedknife inspection is crucial to having consistent, predictable performance from your mowers. If your bedknives aren’t “spot on”, could you expect your turf surface to exhibit any sort of consistency?

One of the most important things you can do to keep your bedknives in good shape is to keep them surgically sharp and maintained with the correct manufacturer’s front and top-face angles.

The front face angle - Grass doesn't always grow perfectly straight up. It grows "up", but generally in several different directions. As a mower moves across turf, the front face angle of a bedknife pushes grass blade tips straight up to be cut by the revolving cylinder blade.

At this point, with a sharp cylinder blade, grass blade tips that have been presented by the front face angle of the bedknife will be scythed off.

This correct angle on the front face is always negative (generally around -5 to -7 degrees for greens mowers).

If the angle is wrong (i.e. a positive or neutral angle), as the mower moves along the grass, the front face can actually push the grass blade tips over (or lay them down) away from the revolving cylinder blade so they won't be cut. This is commonly referred to as “ragging”, as the turf surface can look ragged from inconsistent cutting. Another common occurrence from the wrong angle being ground on the bottom blade is the appearance of a "beard" of grass blade tips hanging off the front face. Grass blade tips fold over the front face and it looks as if the bedknife has a beard. Many of you might have seen this before?

The top face angle - The top face angle of a bedknife ensures that once grass blade tips have been cut they are properly ejected away from the cutting point. This angle must be negative as well.

If the angle on the top face is not correct (i.e. positive or neutral angle) grass blade tips will not be properly ejected from the cutting point and clippings will begin to collect on the cylinder. Eventually the reel cylinder will get clogged up with excess clippings.

Tools of the trade

To ensure your bedknives are in good working order, it is always good to keep a facing tool handy like Bernhard and Company’s Rapid Facer. A quick and easy facing tool will allow turf managers to apply a touch-up grind to the front face of bedknives, keeping them in good working order.

In addition, Bernhard’s also carries two new tools to take an up close and in-depth look at their grass blade tips.

A Macroscope allows you to examine turf in detail. This tool gives you an in-depth look to see exactly what is happening to your grass blade tips after cutting. Are they bruised and ragged, or turgid and green? The macroscope allows you to see for yourself.

A Prism Gauge shows you how your cutting units are performing. Are they all operating at the same height of cut and leaving smooth, clean edges? The prism gauge allows turf managers to view the cut and condition of their turf after being mown. Observe the blade tips, determine height of cut and guarantee consistency all with the prism gauge. Easy to view ruler and magnification glass make this the easiest tool to see what is really happening with turf.

It might be surprising, but you can drastically improve the quality of cut you achieve at your facility every day just by paying a little more attention to your bedknives. Again back to the basics – a good cut means healthier turfgrass, smoother surfaces and better working cutting equipment. As turf managers attempt to establish ideal turf standards at their facilities, they will try lower heights of cut, rolling, low fertility and low irrigation, but I’m sure many would be amazed at the instant impact of a well adjusted, sharp bedknife.

Previous Tips & Tricks

Q. After assisting at as many tournament as you have, can you give us some of your favourite tips & tricks that you have come across?

A. Tournament time is all about presentation time. Your golf course becomes the main focal point for players, media and golf enthusiasts who tune in to watch the event or attend the tournaments. There are a few things that can be done, easy things, to make course appearance that much better, and the playing surface that much more consistent:

• Ensure that all cutting units going out to cut greens are filled with equal amount of gasoline. This will ensure that the weight of each unit is roughly the same – giving a consistency on each green.
• When mowing greens, instead of turning on the collars (potentially causing varying heights of cut on the collars), place a piece of scrap carpet or matting on the collar where the cutting unit will be making its turn.
• Check front and driver rollers to make sure they are consistent (true) and are the same weight.
• Set-up your maintenance facility so that when each piece of equipment returns from the course it can be easily inspected for sharpness, height of cut and adjustment. Each piece of equipment should be pulled into the shed facing the direction it will be taken out of the next time it is used. If a machine does not pass inspection move it away from the machines that have passed and will be used on the course. Only allow machines that you have checked and deemed “acceptable” should be facing out, ready for use.
• A tip I received from Chris Gardner, equipment technician at Oakland Hills Country Club (Host to the 2008 PGA Championships), if you have the space/maintenance area to accommodate, never allow your machines to be reversed in the maintenance area. According to Chris, problems can easily develop on machines that have to be reversed in a busy maintenance facility area, so always point them in the direction for which they will be travelling.
• Always try to use the same mower on the same green – this will help with cutting consistency on each individual green. If the mowers are all cutting at the same height of cut, surgically sharp and are of similar weight – each green should play and roll consistently.

Q. My mower doesn’t seem to being cutting as good as it should be. Is there a way to make it perform better without sharpening it?

A. Use a machine like our Rapid Facer to refresh the edge of the bedknife.

If you are running with contact try to open a small gap (about the thickness of a piece of paper, or use one of our "cutting strips" as a gauge) to see if you units will stay on cut for longer.

Ideally, you would give the reel a quick "tickle" on an Express Dual which will give better results than any alternative.

Q. Can my Express Dual be used for anything besides reels/cylinders?

A. Grind groomers regularly for sharpness and uniformity, to ensure the health of the crown and horizontal stolons. Dull groomers act like crowbars, smashing through the rhizomes. For the same reasons, sharpen verticut reels to reduce load and minimize mechanical damage to rhizomes and root hairs. The side edges of groomers and verticut blades should be dead square. That’s where the cutting actually takes place.

Q. When is the best time of year to sharpen for cool-season grasses? I generally sharpen just in the summer time.

A. Reconsider the timing of your reel sharpening. Sharpening reels just prior to high stress periods can reduce disease conditions. Two key times to sharpen are in the spring and the fall. Sharpen in the spring as your grass is coming back from winter dormancy – allowing the swards to grow in healthy, stronger and more resilient to disease. Sharpen in the fall for the same reason – grass will remain stronger and healthier throughout the dormant period due to the high quality cut applied. Also, it is a good idea to sharpen your cutting units just after applying top-dressing, which can make your cutting units dull.

Q. What would be a benefit of grinding grooved or wiehle rollers?

A. Spin-grind grooved or wiehle rollers to true them up for uniformity. Consistency across the green is as important as consistency from green to green. Imagine a triplex greensmower with one set of rollers “square”, one egg-shaped, and one properly round. One unit would hop-hop-hop across the green, the middle one would wobble-wobble-wobble and the third would roll-roll-roll. Important: After grinding grooved rollers, put a half-round file on each groove to dull the edges of each roller section.

Q. I seem to be going through a lot of bedknives lately. How can I extend the life of my bedknives?

A. Simply touching up the front face of the bedknife every week on greensmowers, every two weeks on tees and monthly on fairway mowers will go a long way toward extending the functional life of a quality grind and save time by forestalling the need to lap.

Q. How do I know if my grinding stone needs dressing and what happens if I don’t dress the stone?

A. There are several indicators that your grindstone needs to be dressed.

• As you increase the feed you are not getting an increased spark pattern.
• Stone does not seem to be removing material, or it is removing material intermittently.
• Surface of the stone looks clogged with metal.

What happens if you don’t dress the stone? Quite simply, you will get a bad finish. Another consequence of not dressing the stone on an Express Dual is you can load the bearings on both the grinder and the mower. Similarly, if the stone is not dressed on an Anglemaster you may not get a straight grind. In both of these instances, the stone is rubbing more than removing material from the blade.