Page 20 - GreenMaster Fall 2023

u DID YOU KNOW? u MIKE ROLLINS, DIRECTOR OF MARKETING & SALES, SIP CORPORATION
A Game of Precision
As your reel diameter gets smaller
from wear and grinding, do you GAIN or LOSE clearance between the bottom of the bedknife and the top of the grass when mowing? This may come as a surprise, butitis a geometric fact that you are LOSING clearance underneath the bedknife as a reel gets smaller.
As a result of relentless wear and grinding, your reel diameter inevitably gets smaller. Regardless of the brand of your mower, this process leads to a reduction in clearance beneath the bedknife. At no point are you gaining clearance underneath the bedknife as a reel gets smaller. Your cutline moves forward, reducing the behind center distance of the reel and putting more bedknife than reel into the canopy. The front face angle changes and becomes more upright, standing up more turf. All of these factors affect your clip yield, and these are only a few examples of what can happen as your reel diameter diminishes.
IMPLICATIONS ON YOUR TURF
In practical terms, if one reel on a fairway mower is smaller than the other four by .100” (due to heavier wear or inconsistent grinding practices), this difference can lead to noticeable differences in your after cut appearance and clip yield.
The smaller reel has less clearance, places the knife deeper into the canopy, and changes the front face angle. Although your
Photo courtesy of EM Justin King from Jamestown Park Golf Course in NC.
Two Jacobsen cutting units – one with a new, 5” reel and the other with an old, worn reel at 4.680”. Both with a new, same part number bedknife. Front roller HOC adjustment, set to .140”. Clearance underneath shear point: New/larger reel was .034” clearance and old/smaller reel was .023” clearance.
20 • CGSA • GreenMaster
height of cut may be the same on each cutting unit on the bench, the actual height of cut on the grass will vary, leading to an uneven after cut appearance and varying clip yield.
Understanding the role of reel diameter is key to ensuring uniformity across cutting units and mowers, which can help troubleshoot issues that we experience in the field. This is just the tip of the iceberg, too. We have not even begun to discuss the
implications for your greens mowers, particularly fixed-head mowers.
Stay tuned for more insights into the mechanics of mowing and how minute changes can dramatically impact the appearance and health of your course. GM