Hi oldmatty, you will find that there are 2 schools of thought here....(1) that you need slight contact and can cut paper and (2) (which is my method) that you have NO contact but
minimal clearance. here is a brief extract from a professional turf care magazine:
Myth: You must have contact between cylinder and bedknife.
Fact: �You do not need contact between the reel and bedknife to cut turf grass. Contact between the reel and bedknife will generate heat which will have many effects on not only the turf grass, but also on the traction unit. The heat generated between the reel and bedknife will tinge the leaf blade. Also that heat can cause the bedknife to expand which will tighten the cutting unit up even more. The tighter the reel - bedknife contact, the more strain this puts on the traction unit which can cause hydraulic hose failure and premature failure of the hydraulic system if fitted�.
Contact between cylinder and bedknife causes drag requiring greater effort to turn the reel and in turn this greater effort has an adverse effect on drive-lines and engines. This drag also leads to rapid wear and loss of sharp edges, as well as a poor quality of cut. With contact you have the undesirable �scissor� action instead of the desired �scything� action. It is the scissor action which damages the turf plant and can prolong the healing process.
You do not need to cut paper...the cylinder reel is designed to cut grass.
The primary chain should have a minimum of 12mm play to prevent chain stretch and primary sprocket wear. All other chains should have slight play as well.
