Is there a better source for prop nuts and washers than os.$19.99 for a prop nut and washer fox a fx91 seems ridiculous,any good aftermarket sources saw east r/c $1.00,any good?

Hardware store.

Personally, I would spend the money for an engine manufactur's prop nut and washer set for your engine. The hardware store nuts will fit your crank, but notice that they are not the black hardened and tempered steel that you get from say, OS, or Saito. They are also a much looser fit to the threads. The washers are even worse, A nominal 1/4" is about 0.030" over sized on the IDand the ODand IDmay not be consentric. They were not made for rotating use. They are really soft steel and will deform when you really tighten the nut down, providing you areusing an OEM nut (set for four strokes). Using the hardware store nut, and washer, well the threads may go before you can really tighten down the nut.

When I first started flying 4 strokes, I heard all kinds of storys about them spitting props. Iat first had trouble with a backfire loosening the prop nut set, but I never lost a prop. I finally decided to really tighten the nut and I've not had a problem since with a four stroke. I have spit the prop off a couple 40 size two strokes though and in both cases, it was a hardware store nut coupled wiht a plastic back plate for the spinner. No tapered lock nut to keep things intact if the engine siezes from overheating or backfires.

Most all, if not all four stroke stock sets have amating nut that centers the hardened washer, then has an internal taper on the front to match the taper on the lock nut. Every thing runs true. With a hardware store replacement set of nuts and washers, you probably are introducing more off balance than you would get from most props today if they had never been balanced.

Just my opinion.

Don

I use spinner prop nuts on all of my engines, 2-stroke and 4-stroke.
Most of them are less than $10.00

TW

You need to use a tight fitting washer but the threads on the nut are moot. The nut is made from a softer material yes but if you over tighten a hardened nut you will strip the crank threads and the nut, if you overtighten the slightly softer nuts you will probably only strip the easily replaced nut.
Oil pan drain plugs are a good example, there is a hardened nut welded into the pan and the drain plugs are made from a soft metal so they wear out first.

Spinner nuts, yes! Dubro makes nicely anodized colored ones too. And his engine is a 2 stroke so it wouldn't need to be double nutted.

Ernie

What is wrong with the grade 8 NF-28 and -24 nuts sold at lowes and HD? I'm sure they are better quality than the OEM stuff.

I think the big box store hardware comment was that the washers are soft and imprecise, and the nuts are not self locking cone double nuts. The nuts were ok as far as hardness, maybe too hard. I use precise washers and nylon insert lock nuts on my prop shafts. They may, (not likely) loosen, but they won't spin off. If I use spinners, use metal back plate types to preclude the softer plastic from deforming and letting the prop get loose. I also use a proper box end wrench, not one of the hobby type tee handle weenie wrenches.

Grade 8 nuts from any source should be plenty good. You might need to sort through a bunch of washers, possibly even metric, to get good fit.

"Hobby shop" alternatives that are not twenty dollars:
http://www3.towerhobbies.com/cgi-bin...?&I=LXK238&P=0

http://www3.towerhobbies.com/cgi-bin...?&I=LXL744&P=0 plus http://www3.towerhobbies.com/cgi-bin...?&I=LXL746&P=0

I don't have a problem finding the nuts so much as the thick washer that fits properly.as vfar as price saito sells their prop washer,nut and locking nut for $5.99 vs os @ 19.99 .

As long as they are the same thread size, the saito should work on the O.S. The only issue may be the washer as some of the saitos I have, have a metric prop shaft and imperial thread size. Or, look at the equivlant size Magnum for a replacement washer/nut set. The one for the Magnum 52 four stroke is only like $6.95 for the three piece set. 1/4-28 thread size.

You are correct about the washer thickness. It is a much more robust washer than you will ever find at even a well stocked hardware store. The hardware store washers are stamped from sheet. The thick tapered prop washers are machined to shape and size.

Don

The Magnum 9 parts http://www.hobbypeople.net/gallery/280208.asp are 5/16-24 thread (same as your OS), and cost $7.95 but are on backorder.

OS branded parts do tend to be expensive.

The Great Planes part in my original reply is only $4.49 for washer, nut, and spinner adapter nut.

Ididnt know we were talking about 4 strokes. Sorry.

But it wouldnt stop me either way. Might be a little heavier to double nut from the hardware store but it would still work as long as it fit under the spinner.

My os 91fx came with the double nut set the same as a four stroke. The magnum washer/nuts for the 91 four
stroke (5/16 shaft) would work.

The 91FX is a two stroke but it uses a double nut setup like a four stroke.

Trying to contact aerowoof, can anyone help me out?

Thanks,
Jim oliver