Best or correct nuts for propellers?

[tronic72]

Just having some new shafts made up and curious about what are the best nuts to use to secure the propellers. Have seen nylon and castellated nuts with split pins and not sure why is most popular today

Thanks.

[Soton]

If you want piece of mind use a castellated nut.

[RaymondR]

Originally Posted by Soton

If you want piece of mind use a castellated nut.

[pcmm]

Originally Posted by tronic72

Just having some new shafts made up and curious about what are the best nuts to use to secure the propellers. Have seen nylon and castellated nuts with split pins and not sure why is most popular today

Thanks.

I have to admit, I've only seen castelleted nuts used on prop shafts, no nylocks. Nuts with split pins are 100% secure, that's why they are used. My shaft uses a nut with built in zinc so no room for the usual lock nut. split pin is crucial in that setup!

[fstbttms]

If you have room on the threads, use a jam nut followed by a king nut and cotter pin. If you do not have room on the threads for two nuts, use a castle nut and cotter pin. Do not use nylock nuts.

[FionaJC]

Originally Posted by Soton

If you want piece of mind use a castellated
nut.

Anything else can fall off or corrode away. Also check your woodruff key. Mine was just iron, I found this out when I diecovered we could go forwards but not reverse. I suspected the gearbox till I looked and saw the sahft turn in both directions. The key had rusted away and only the taper was keeping it going round.

[wrwakefield]

We just went through this ourselves a couple of weeks ago.

You didn't say what size shaft or propeller type, but double nuts are best if your prop didn't include fasteners. Include a hole in the end of the shaft for a cotter pin safety immediately behind the [tightened in place] nuts.

Remember to fit the prop correctly; lap fit it to the shaft taper, fit without the key and mark shaft; fit with key and make sure it gets to the same mark, otherwise the [bronze] key may be stopping the prop before it is fully on the taper. Torque the prop onto the shaft using the larger of the two lock nuts. Then remove that large nut and torque on the smaller nut- locking it in place with the larger nut. Install a thick cotter pin behind the nuts as a safety. [The hole (3/16" on my shaft) should just be revealed once the two nuts are torqued in place so the cotter pin is against the aft side of the large nut- preventing it from backing off.]

FstBttms posted a good photo of the finished results I describe in his reply [above.]

Mainsail also has a good write about properly fitting a prop.

Best wishes with your project.

Cheers! Bill

[etterridge]

My CDI feathering prop specified nyloc.

The but did not fail, despite all predictio s to the contrary.

When the prop lost it's blades I attached the new fixed-pitch prop with a castellated but. As thean said, it's for the peace of mind.

Derek

[CapnBazza]

It doesn't make me happy but mine is fitted with a nyloc nut and has been for 30 years without (touch wood) losing a prop. If there was room I would change it but there is no hole in the shaft, no room for one and not even room for a half nut. I have replaced the nyloc nut with a new one and if it does not fall off in the next 30 years I will stop worrying.

[Orion Jim]

Originally Posted by FionaJC

Anything else can fall off or corrode away. Also check your woodruff key. Mine was just iron, I found this out when I diecovered we could go forwards but not reverse. I suspected the gearbox till I looked and saw the sahft turn in both directions. The key had rusted away and only the taper was keeping it going round.

I must admit this is the first time I've ever heard of an iron woodruff key. You learn something new every day.

[01kiwijohn]

I prefer split pins but, have used nyloc and it never came loose. Then again, I torqued it to the standard spec.
On one occasion, I used a regular galvanized nut, from a local hardware store and, despite my apprehension, it looked just find when we hauled out, three months later.

[robert sailor]

I like bronze nuts for prop shafts.

[UNCIVILIZED]

Originally Posted by wrwakefield

We just went through this ourselves a couple of weeks ago.

You didn't say what size shaft or propeller type, but double nuts are best if your prop didn't include fasteners. Include a hole in the end of the shaft for a cotter pin safety immediately behind the [tightened in place] nuts.

Remember to fit the prop correctly; lap fit it to the shaft taper, fit without the key and mark shaft; fit with key and make sure it gets to the same mark, otherwise the [bronze] key may be stopping the prop before it is fully on the taper. Torque the prop onto the shaft using the larger of the two lock nuts. Then remove that large nut and torque on the smaller nut- locking it in place with the larger nut. Install a thick cotter pin behind the nuts as a safety. [The hole (3/16" on my shaft) should just be revealed once the two nuts are torqued in place so the cotter pin is against the aft side of the large nut- preventing it from backing off.]

FstBttms posted a good photo of the finished results I describe in his reply [above.]

Mainsail also has a good write about properly fitting a prop.

Best wishes with your project.

Cheers! Bill

Thanks for the linked tips!

[tronic72]

Hi Everyone,

Thanks for all the tips. We went with a castellated nut.... of sorts.

We got these from martyr. They incorporate an anode mount into the nut. Seemed like a good solution to two problems and no anode is required on the shaft with these fitted.

The nut is slotted to allow for the split pin. It is made of bronze and uses a 316 stainless Allen bolt to secure the anode. It wasn't cheap but I think is worth the extra dollars.



Thanks for all the replies and advice.

[UNCIVILIZED]

Loctite on the allen bolt? Red, or?