Just snickers at the dremel tool for this ;-}
The sprocket is 1/4" thick chromium steel with a 1 3/8" hole, you need a 1 7/8" centered hole to fit over a Nexus 3-speed hub.
I have far beefier grinding tools than a whimpy Dremel like a real drill press with carbide metal cutting rasps and didn't bother to even try knowing how futile and inaccurate that would be.
There is also another issue, once you get to mounting the sprocket you'll find that hub also has a lip for the spokes and getting the mounting bolts to fit that close to where the spokes mount just adds to the frustration.
Then as if to just add insult to injury, that is not just a dust cover on the left, it is an integral part of the mechanics, the brake arm is permanently attached to it, and it needs to spin on the hub right where the sprocket is or the hub won't spin.
So just to reiterate my warning about mounting a DD sprocket on a Nexus 3-speed hub... DON'T unless you budget in a bolt on hub sprocket mount, it just isn't worth all the hassle just for pedal side gears.
The really sad part about this story is I also have a new high performance Macargi Pantera 7-speed shifter build in progress here.
The only real
difference between the Tahiti and Pantera is the hub and the HP shifter would of had no problem and frankly I think would have been better with the 3-speed and the DD customer happier with a 7-speed to pedal along.
Alas, the Tahiti's rims are frigg'n RED
and that would have blown the whole look of the shifter bike so a no go.
Oh well, live and learn, and hard jobs as well as failures are teachers in themselves, this was just an exercise in learning from mine ahead of time ;-}