Front sprocket issues again

[Lawrence]

Paul you might be right, I remember a few years ago a friend of mine put the modified nut on backwards after the first nut fell off, he was thinking along the same lines as you he used a 3 mm washer drilled out to fit over the splines between the nut an the tab washer to ensure the tabe washer could the located on the spines properly. There was about a 1 mm gap of play between the sprocket and the washer.
He always thought the nut should not be tight against the sprocket. I checked with him after reading the post and he never had the problem again. He still has the bike but cannot use it due to a back problem and there is 33000 miles and 2 sprockets with the same nut and tab washer.

Hope his isn't like mine then, mine fell off at 33500  :lol

Certainly something to think about come sprocket change time.  The best option, regardless of whether the nut is tightened against the shaft or the sprocket, has got to be the circlip/bolt+washer or similar to stop the nut actually falling off if it does come loose.