Some quill bolts are for sale here :
But you'd have to figure out exactly what size you need, maybe borrow somebody's vernier caliper.
If you're like me, you go into the garage, mount the bolt in the chuck of an electric drill, get out the dremel, get into your eye goggles, and HAVE AT IT !!! with both electric devices going at 2000 x 20,000 = 22,000 revolutions per second with a flap wheel !! In just seconds that that stem bolt will fit PERFECTLY !! Then polish it with 2000 grit paper and brush chrome it with a set from http://www.caswellplating.com !!!
- Don Gillies
San Diego, CA