What is Clip?

If you have any reel mowers it is important to understand what clip is.  When we talk about cutting units, the term clip is used to explain the distance between cut marks in the turf.

To fully understand clip, you need to understand basic cutting unit theory.  A reel will gather grass before it cuts it.  At a magnified level you will see waves in the grass after any reel has cut it.  The distance between the bottoms of these waves is your clip.  This is why crosscutting still produces clippings, and makes for a smoother surface.

There are several factors that determine clip.  The number of blades on the cutting unit, the speed of the reel, and the speed of the machine.  It is important to match your clip to your height of cut.

So how do we make sure it matches?  To start, we need to make sure we have the correct reel for the job.  Make sure you match your height of cut to the number of blades. Next use the reel speed charts to correctly set your reel and traction speed.

Reel chart on Greensmaster

Can we have a clip too small? - under certain conditions you can have a clip that is too small.  Think of trying to use a 14 blade reel to cut heavy grass at 1.5 inches.  There is just nowhere for the cut grass to go.  The other thing you can see is your clip will be so close you are introducing more stress to the turf.  I compare it to double cutting every day.  Under certain stressful situations you may not want to introduce more stress.

Clip Marks in turf

If this shows up on turf that normally looks fine.  You are typically seeing either an operator going too fast, or a reel that is not spinning fast enough.  If you can slow down and the problem goes away, then you are fine.  If you have to slow down more then normal, or slowing down is not helping, the reels are not spinning fast enough.  At this point try to adjust the reel speed faster.  If the reels don't spin faster, you are looking at a hydraulic issues. 

Reel Speed adjustment on 5010 series Mowers

The two biggest things I see contributing to this are o-rings in the reel control cartridges or reel motors worn.  It is important to remember that one worn motor can cause a series of reels to slow down.  One motor on a triplex, will slow down all three, one motor on a fairway unit will slow down either all three of the front or both of the rear.  In a future post I will cover testing reel mower wear.