ap: You're like the coolest mom ever. My mom doesn't know the diff. betw. an X-mart bike and a "y-mart" bike, hehe.

One last plea...check out ebay. I've done really well on ebay buying AND selling. You could sell the Carbon Lefty and get the adjustable one. There shouldn't be a terrible weight penalty, and the bike would be built right. It just scares me to think you would mill down the head tube to fit a fork that's not made for the bike.

I guess there's a bright side. It doesn't sound like your boy is too terribly aggressive, right? Just XC riding/racing? Maybe a few mm of head tube wouldn't matter. For me though...I'd be afraid that I'd end up snapping the head tube off or something catastrophic.

As Gastro said though...don't use a grinder. Use a "facing tool" to take it down.