Whoops, I was wrong. According to, http://www.boltscience.com/pages/screw2.htm Thury IS 47.5 degree angle. alan@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx www.alanstepney.info Model Engineering, Steam Engine, and Railway technical pages. MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.