Frankenstein...Friend
Basic terms you'd just be drilling and tapping and inserting a stud to replace the worn threads.
What is the thread ? and shoulder diameters? and length ?
A lawn mower wheel bolt may work, depends on the size. Would have to cut to length.
http://www.ebay.com/itm/ACE-72557-Wh...gAAOSwImRYSEpv
http://www.ebay.com/itm/Perfect-Part...kAAOSwKrhVd1Fs
Item description
•Fits all wheels with 1/2" bore
•3/8"-16 thread size
•9/16" to 2 1/4" shoulder length