there are recessed sleeve nuts of various lengths, but the back side of the hole in the fork has to be enlarged to suit.
You realize there is a bolt on adapter* for BMX bikes that will let you fit a V brake , and one for U brakes too, no brazing needed ..
* the bolt can be generic 6mm ..
but why not just buy a new brake caliper that fits? and is the right reach.
Last edited by fietsbob; 10-02-13 at 12:42 PM.