The Benefit in Grind

By Dave Saltman

Now appearing in Pitchcare!

Dave Saltman at Pitchcare recently invited Bernhard and Company to the Wolverhampton FC training grounds to see the benefit in a grind. With all the stress, traffic and sand football pitches receive throughout a season we wanted to help the Wolves groundsman maintain a keen edge on their blades, keeping turf consistent and healthy. Click the link below to see the article or pick up the current issue of Pitchcare to read it.

Recently I invited Bernhard’s to the Wolverhampton Wanderers FC Training ground to grind our cylinder mower units and bottom blades.

With all the renovation works now nearly two months behind us, the dressings previously supplied and applied have now worked themselves into the surface.

Since the grass has germinated, regular mowing has been carried out to help establish a good sward for the coming season.

As with most clubs, Wolves would have the machines ground annually, usually at the end of the playing season. This would normally be deemed sufficient, unless one of the machine cylinders got damaged with a stone, peg, coin or other miscellaneous object inadvertently mown over.

While I and the staff tend to check and re-set the mower blades prior to each mowing operation, it would be true to say that the cut can, on occasions, not be of the quality expected from a recent re-grind. In fact the cut, probably does deteriorate as the season continues. Moreover the use of top dressings helps to wear the blades and, given that many winter sports pitches are sand based, the wear continues through the season. The trouble is that with only a week or two’s window to get the machines overhauled between renovation, and the new grass starting to grow vigorously, the newly sharpened mowers have to start work on recently top-dressed surfaces.

So, as an exercise, we asked the Express Dual team to service the cutting parts of our John Deere 5 gang fairway mower, one Dennis Premier and two G860’s.

The equipment consisted of the Express Dual 3000 and the AngleMaster 3000, standard equipment for many golf courses around the world.

Richard Kerrigan, Senior Technical Trainer, set the two machines up in the garage. Within a few minutes the grinders were ready to go, and Richard and Steven Nixon (Sales Manager- UK and Ireland) were removing the five units from the ride on mower.

Removing, first the units from the machine, and then the sole plates from the units to get to the bottom blades didn’t take the lads very long. Richard mounted, in turn, each of the bottom blades on the AngleMaster and skimmed them to the required angle and trueness. Similarly, each of the cylinder units took their turn to be spun and given a new shiny edge. The whole operation, including fitting the units back on the John Deere took less than an hour and a half.

Steven said, “Our idea for grinding is to run no contact between the cylinder and the bed knife, but to do that you need to have two very sharp edges. We sharpen the blades and when the unit is set up, we allow about 1/1000 of an inch gap. If you don’t maintain that sharpness, then the tendency is to close this gap, so that the cylinder and bed knife touch. When people do this, the blades act like a pair of scissors instead of a scythe, squeezing the blades of grass to cut, rather than cutting cleanly.”

“These days, manufacturers cutting machinery is built to be accessed quickly for grinding. All of the main manufacturers produce easily removable units for this purpose.”

“We do work on the principle of grinding more regularly to maintain a non-contact cut, but this process ultimately creates less wear on the cutting parts and less overall stress to the machine’s engine and other working parts. In our experience a well-maintained, regularly sharpened cutting unit extends the life of cylinders and bottom blades.”

“Keeping the front cylinder face sharp is the single most important factor to quality cutting. Maintaining a keen edge on the blades will improve the quality of the grass. Once the blades are sharpened the turf appearance will look visually better, and with that comes a healthier plant. It is true to say that when a mower delivers a fine neat cut, there is very little bruising to the leaf, the wound is small and heals quickly, not allowing pathogens much time to access the plant.”

“Less tip damage reduces bleeding, but will also lower growth rate which means more nutrients are retained in the root, helping to produce a better and healthier root structure. A sharp cut also means that the plant diverts far less energy to heal or stave off pathogens, so there is less need to take up extra nutrients and, therefore, fertiliser use can be more infrequent. The resilience of the turf also helps with recovery from foot/boot damage. This is particularly important during the colder months when the plant is less active. Poor cutting just compounds the stress on the plant.”

“With less bruising and tissue damage, the plant doesn’t require so much water uptake to repair, also less tissue damage means less evapotranspiration, allowing the Groundsman/Greenkeeper to decrease the use of irrigation.”

“Another benefit to keeping sharp blades is that the grass blade tips appear much greener because there is less cellular damage from applying a sharp cut. When you tear grass blade tips, causing cellular damage, the result is sclerosis (yellowing) of the blade tips.”

By mid afternoon all of the cylinders had been ground, fixed back into their respective units and set up. The Wolves staff then took the machines out on to the youth team pitch for a run out to see the performance.

As you might expect, it was clear to see the immediate difference, both in the quality of cut up close and the visual appearance of the turf from a distance. So perhaps there’s a benefit in more regular grinding. Clearly in golf, many courses invest in grinding equipment as an essential part of their machinery capital expenditure, so why is this not the norm at professional football/rugby clubs?

I asked Bernhard’s to provide Wolves with a cost comparison based on our available machinery. These costs don’t incorporate the other benefits such as flexibility in your schedule; being able to grind when you need to, without losing productivity (little down time), as well as all the already mentioned turf benefits. Perhaps owning the grinders is a solid investment?

These machines are also backed by a 10-year limited warranty and retain their value.

Cost comparison of owning grinders vs. contract grinding

Based on cutting heads (amount at Wolverhampton FC training ground) and the same grinders supplied.

Owning grinders:

3000 Express Dual and Anglemaster: £3900/year for 7 years (fixed price)

To sharpen 15 heads (1 hour/head) = 15 hours

Groundsman ~ £10/hour x 15 hours to sharpen

Cost: £150 every time Groundsman sharpens.

Sharpening 2x a year = £300 + £3900 (fixed cost of grinders per year) = £4200/year to own grinders

Sharpening 4x a year = £4500

Contract grinding:

£130 per head (not a fixed price - price will vary from one year to the next)

£130 x 15 heads = £1950 (Cutting units are out of the shop for +/- 14 days, not able to cut.)

Contract grinding 2x per year = £3900

Contract grinding 4x per year = £7800