Trumpy,
Thanks for the help.
Taking your advice I'm going to look for a different model saw, older probably, and forget about modifying the one I have.
Makita would say not to use the saw for anything than what it's designed for. However, I see the Americans doing this sort of mod all the time because a dedicated dado machine runs to around £3000 which, for me, a simple carpenter, is just out of the question.
If I ever do get round to this then I'll make sure it's as safe as can be made, substantial guards etc.
Regards
Dave
