Just to machine ring gear step? No other machining?

That is correct.

Maybe I've gotten lucky but in all these years I've been working on boats, I've never had to weld a ring gear in place nor have I had one come off or slip. Done quite a few of them. Unless it was a loose fit to begin with, I just haven't seen it.

They fit really snug I just welded them for moral support. Lol

Moral support exactly. Without welds I'm relying solely on the skill of the machinist. Sorry to say I haven't met a machinist / builder yet I will do business with again so far.

I am far from a machinist but to do some simple flywheel work is nothing if a shop cant handle that they should shut the door. I was to cheep to give 450+ for a aluminum flywheel so I made two for my self and its a very easy thing to do. The 150 to machine the ring gear is robbery sorry you had to pay that.