65, 72, 80, 82, 91 Engines: These engines use a 7x1 mm thread. Use
Tru-Turn Adapter Kit TT-0718-A (7x1.0mm/8mm); this adapter does
not have a jam nut. Another adapter TT-0717A has a jam nut and is
the one recommended on the Tru-Turn web site..

Got the above from the Saito site... , So I guess their saying to use the
TT-0717A.... You always want a double nut on 4c's.. I use a T.T as
Gary..... It's a 2 & 1/2" Only problem so far...... The engine is on the 4*
And the spinner is on the Profile....... They both flew Great this morn..
If I ever get it on the "Do".... I'll have to go with Barry's way... Since I
bought a Higley.... It sort of looks like a button on a fur coat..... Ohhh
wrong story...... Let's see.... a set for the O.S's , Mag, YS.... And now
I need another adapter for the Saito.... This is a lot of fun...

I'm liking the 16X4W.... The 15X6 is still in the bag... I gotta try it though..