The Benefits of Relief Grinding
When it comes to reel mower maintenance, the method you choose for grinding cylinders can have a huge impact on performance, cost-efficiency, and long-term durability. While spin grinding may offer a quick solution, relief grinding remains the gold standard for professionals who prioritize machine longevity and a consistently clean cut.
So what exactly makes relief grinding so beneficial?
What Is Relief Grinding?
Relief grinding involves removing metal from the back side of the cylinder blade, preserving the original diameter of the reel. In contrast, spin grinding removes metal from the cutting land of the blade, slowly reducing the overall diameter of the reel over time.
While spin grinding may appear faster and simpler, it results in quicker blade wear and more frequent regrinding. Relief grinding, on the other hand, is a long-term investment in your equipment’s performance.
Key Benefits of Relief Grinding
✅ Extended Blade Life
Relief ground reels and bedknives last significantly longer than those that are only spin ground. Since the cylinder diameter is preserved, units can go up to three times longer between grindings. Bedknives, in particular, can last 2 to 4 times longer, saving both time and money in replacements.
✅ Reduced Friction = Lower Operating Costs
Less contact between the reel and bedknife means lower friction during operation. This directly translates to:
Lower fuel costs for combustion engines
Lower power draw for electric or hybrid mowers
This is especially valuable as more turf managers transition to electric equipment, where power efficiency is crucial.
✅ Extended Service Life for Machine Components
Relief grinding puts less stress on engines, gearboxes, transmissions, and other moving parts. Lower mechanical resistance means your entire cutting unit experiences less wear and tear, leading to longer intervals between maintenance and fewer breakdowns.
✅ Fewer Adjustments Needed
Because wear is reduced, the reel-to-bedknife setup stays consistent for longer. Fewer adjustments are needed, which saves labor and reduces the risk of misalignment issues.
✅ Improved Cutting Performance in Harsh Conditions
In dry summer months, grass loses its natural moisture and lubricity, accelerating bedknife wear. Relief grinding mitigates this, offering a cleaner, sharper cut that stands up to tough mowing conditions — even in the wettest weather. Say goodbye to tearing, ribbing, and skidding.
✅ Less Backlapping Required
Backlapping can extend cutting edge life, but it’s not without controversy. One crucial point: if you choose to backlap, your reels must have a relief angle. Without it, the paste won't reach the true cutting edge and will instead polish the non-cutting side — offering little to no benefit. Relief grinding ensures your backlapping efforts are actually effective.
What the Manufacturers Say
Different manufacturers have different recommendations for reel-to-bedknife setup:
John Deere and Jacobsen recommend no contact between the reel and bedknife.
Dennis, on the other hand, suggests a very light contact setup.
Regardless of approach, relief grinding makes it easier to achieve the recommended settings. Spin ground reels, which have a wide cutting land, make light or no contact settings difficult — leading to more heat generation and faster bedknife wear.
Relief Grinding = Long-Term Gains
Spin grinding may seem like an easy shortcut, but it’s just that — a shortcut. With spin grinding alone, you're forced to regrind more frequently, replace parts more often, and deal with degraded cutting quality much sooner.
Relief grinding provides a sharper edge for longer, with less downtime and less cost over the life of your machine. And let’s not forget — you should only grind your reels when they’re no longer sharp, not just because your method requires it.