Hi Neg... my apologies.. I just re-read your post and realised you are wanting to enlarge blade holes to suit a 30mm bore.. I was thinking the opposite.. That's the only problem I've ever had.. sorry.. yes good luck with that.. I will be interested to learn how that's done..

I guess Bung's machinist suggestion could be a good option.. you would think that wouldn't cost too much to do. And you could still use them on your own saws.. utilizing a smaller bush...

Good luck with it. And enjoy the use of some nice equipment..