I just built a seat post for my PGN-10. (Stupid French sizing!) I found a post at budget bicycle center in Madison, WI. I cut a wedge into the post and found a thin 12" bolt and a large metal wedge. Then you take a drill and put a hole in the top of the post to take the bolt and bingo. I've been happily riding my resurrected Peugeot for a year now!