Securing prop nut

zoidberg

zoidberg

Well-Known Member
Joined
12 Nov 2016
Messages
6,937
Visit site
I'm advised I'll want to secure my 'new prop nut' onto the 25mm shaft with more than simply Nyloc and a tab washer.

It seems there are options: One is to drill through the nut and the shaft, out t'other side, and fit a splitpin. Next option is to drill and tap the nut, then insert a grubscrew into a 'dimple' in the shaft. Loctite optional.

How much 'belt and braces' would you recommend?
 
zoidberg said:
I'm advised I'll want to secure my 'new prop nut' onto the 25mm shaft with more than simply Nyloc and a tab washer.

It seems there are options: One is to drill through the nut and the shaft, out t'other side, and fit a splitpin. Next option is to drill and tap the nut, then insert a grubscrew into a 'dimple' in the shaft. Loctite optional.

How much 'belt and braces' would you recommend?
Click to expand...

After all that, you should really hammer the hell out of any exposed threads, then weld it.

I'd call nyloc and a tab washer "belt and braces". How many locking methods do you really need?
 
Tab washer is fine. Nyloc is OK but really not necessary but no harm in having that as well. Under what circumstances can you imagine a prop nut coming undone if either tab washered or pinned? If the taper and prop are matched there is no reason for the nut to be under any pressure at all. It is usually moer of a problem actually getting the nut and prop off when you want to as I will probably discover tomorrow morning!
 
As another option, Darglow use a pair of Nordlock washers, Loctite and plain nut for their Featherstreams when fitted to a shaft.
 
Drilling a stainless prop shaft will be hard work, with the risk of work hardening it so you can't make it all the way through.

As long as the tab washer can engage into its slot and it's bent up against the nut, the nut isn't going anywhere.
 
Have stainless tab and nylock on both my Mobo shafts and props.
Not easy drilling shafts expecially if shaft is still on the boat.
Stainless is not that bad on the bench with a pillar drill and good chance the hole is at 90 degress and in correct location on shaft.
Lying under the boat with a hand drill is different kettle of fish .Ever tried to extract a broken drill, especially the first fragile pilot drill.
In the future easier to replace any prop which will almost certainly come with different size boss and no grief extracting split pins.
Just torque up nut, no faffing trying to get the nut in exactly the correct spot to align split pin/hole/ castellated nut as the rain runs down your neck.
 
Last edited:
You must log in or register to reply here.

Share this page

Top