I hope to get over to meet Brett some time. I am a little machine crazy myself and always looking for methods to chuck odd items in lathes. This photo he has a fork chucked with a fixture in a 3 jaw chuck and cutting the stem threads. The lathe is a Holbrook capable of metric threading. The photo is upside down. Machinist are a little twisted anyway.
http://www.biketoolmaker.com/Site/Photos.html#22