Hi all;
I have an OS70 Surpass I'm breaking in on a H9 cub. I'm using an old CG spinner for now, but I want to use a Higgley Hub when I mount the cowl. The OS has two prop nuts, one main and one "safety". If I use the Higgley, I can't use the factory nuts. Will this be a problem in the event of a misfire? Will it throw the prop?
Thanks!

It can throw the prop. Be extra carefull not to overlean the engine and you should be OK.

Put one of these on first, then the hub
http://www2.towerhobbies.com/cgi-bin...?&I=LXL744&P=0 aluminum
http://www2.towerhobbies.com/cgi-bin...?&I=LXL761&P=M brass

I don't use the Higley hubs, but do use the DuBro nuts/spinners and always use one of the engine's nuts and then the DuBro unit as the jam nut. Won't this work?

I have prop nuts currently running on three different engines--two four strokes, and one two stroke. I have in the past ran prop nuts on four strokes up to a saito 100. I just put the prop on, washer, and then prop nut. Use an 8 inch crescent wrench to tighten real good, and have never had one thrown off. Of course, I run all of my engines (especially the four strokes) a little on the rich side. I also CHECK THE PROP NUT VERY REGULARLY to make sure it hasn't loosened off. I've never had one so much as loosen. I have, however, had a two stroke throw a spinner and prop off using the factory nut. Props can come off of any engine, any time regardless of how many nuts you have on them. The key is GET IT TIGHT. Some people are afraid to tighten their prop nuts. The shaft is hardned steel. It will take a lot of force to strip the threads, and likely the nut will strip first.
I have to admit, though, the Higley nut that replaces the washer looks interesting...

Thanks!
The washer that came with the engine has an oversize hole and the main nut has a shoulder that engages the hole, cnetering the washer. Obviously I can't use the factory washer with the Higley Nut. Does the nut you show from Tower replace the washer?

Can't you use the stock washer and the nut you describe above and then have the Higley hub act as the jam nut? Keep in mind that all that's needed for fully effective holding power is about 1 1/4 to 1 1/2 turns of the nut (in your case the hub), so thread length shouldn't be a problem.

Yes, it replaces the washer.