i had a problem like this on my rc8 where the rear gearbox halves were held together by cap head screws screwed into plastic and they kept rippin out i just bought some m3 stainless threaded rods off e bay and cut them to length and put nyloc nuts on either end job done!! alot easier than machining tool steel that dia and length, or i could do 2 rods to your spec out of titainium for about 25 quid all in? or tool steel/silver steel for around half that price?
http://cgi.ebay.co.uk/M3-x-100mm-A2-...item4157b5b07f
hope this helps
cheers gixxer