Harry Higley also makes the 5 mm safety spinner, (hub). I just ordered one thru my LHS. They make a large, THIN, aluminum nut called a lite lock. It is used in conjuction with the hub, forming a jam nut. I know they make a brass, heavy version of this lock nut too. (not sure about the 5 mm size). On my one .40 size plane....... I am using a heavy, AND a lite lock, plus the HUB. That combo gets the weight all the way forward. In the 7mm size the heavy lock weighs 1/2 oz.

http://members.aol.com/harryhig/SpecialDiscount.htm

Harry has some other cool stuff too!!! Order the catalog, or get one free with your order............. ...lownslo.......