RD-18 Flywheel Nut Size?

[Mas]

Anybody know the size nut for a '56 Johnson RD-18 30 HP Electric crankshaft/flywheel?

Mas

 

[F_R]

Re: RD-18 Flywheel Nut Size?

Anybody know the size nut for a '56 Johnson RD-18 30 HP Electric crankshaft/flywheel?

Mas

I know it takes a 7/8" wrench. I don't have one to measure the thread size.

 

[Mas]

Re: RD-18 Flywheel Nut Size?

I think it's 9/16 x 12...but I'm not sure.

Mas

 

[F_R]

Re: RD-18 Flywheel Nut Size?

I think it's 9/16 x 12...but I'm not sure.

Mas

More likely 9/16-18

 

[Mas]

Re: RD-18 Flywheel Nut Size?

Ooops...that's what I meant 9/16 x 18. Times 12 would be really coarse!

Mas

 

[Tim Frank]

Re: RD-18 Flywheel Nut Size?

Ooops...that's what I meant 9/16 x 18. Times 12 would be really coarse!

Mas

Nope....9/16-12 is the regular UNC thread.

 

[Mas]

Re: RD-18 Flywheel Nut Size?

What's UNC? ...besides the "Heels?

Mas

 

[Tim Frank]

Re: RD-18 Flywheel Nut Size?

Good question....I think it means "Unified National Coarse", the thread series, whereas 5/8-18 is a UNF series thread. UNF meaning the same but Fine.
The "U" could be siomething else...United etc.
Someone will chime in if I got that wrong.

 

[rjezuit]

Re: RD-18 Flywheel Nut Size?

I believe it is 1/2-20. 1/2"(.500) outside diameter, 20 threads per inch