flyinfriend.... I don't know if my insert is well worn... But I use the small hole
of the insert on both my rounded prop nuts and my -3" size T.T. spinners and
it has been working great.., this is on both the 2 & 4c's... OS..YS's...Saito & a
Mag... I do "carefully" use a bit more pressure and insure it is centered well
on the Higley rounded prop nut before starting, If not, they will dance on you..
I also use the same on the double nuts of the stock setup, as long as the nuts/
shaft will not bottom out in the insert/nut.... But all my engines starts up good
and fast... So I may be just lucky.....