Hi Folks,
I just thought I would provide some feedback about backlapping.
I have a Kermit green Rover - Scotty that hit a screw in the grass and threw the alignment of the reel out. It looked as though it bent the bed knife so I sent it off for spinning grinding and a new bed knife.
On receiving the mower back I noticed a different noise to my last grind and it sounded like the reel was making hard contact with the knife. On inspection it turned out the bed knife hadn't been ground true and to make contact across the full length of the bed knife he had tightened it up significantly. It was so tight that in one spot the reel was so tight that it flexed the bed knife slightly as it passed over.
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In fear of doing damage to the sole plate I quickly lifted the reel up to minimize contact but found then the reel only contacted the bed knife on the outer edges. I was pretty disappointed that I had spent $140 on this considering that he had advised that they grind both together to ensure a true fit.
I found a post regarding having to bed a newly ground reel in via backlapping. I then contacted Cameron in Sydney and he confirmed that if the bed knife is not ground whilst assembled in the frame, it can also lead to it not being perfectly aligned to the reel. So I got myself some backlapping paste and set to work.
The whole procedure didn't take long at all.
Take off the chain cover.
Undo the cutter chain.
Get a 3/4" socket and adapter for my drill.
Adjust the reel just off the bed knife so it flaps a piece of paper when it spins.
Rotate the reel in reverse and apply the paste.
You can hear it grinding away and after a couple of minutes the sound changes and the reel and knife become aligned. Depending on the degree of bow in the bed knife you may need to lower the reel slightly and apply more paste.
When I was happy I then hosed off the compound and re adjusted the reel to make ever so slight contact to the knife. When you rotate the reel there is no resistance and it's now cutting paper. The quality of cut is now great and the reel is no longer making a grinding noise when in use.
I suggest backlapping is a technique that all Scott Bonnar owners should become familiar with to improve the quality of cut.
Cheers
