Prop nuts

[Lou_tribal]

This guy has the tools you need:

L.

 

[eyschulman]

Ok is this a dumb question? Why not epoxy the whole thing together. Do the proper fit including key and then use epoxy on prop key and nuts. This should keep water out and decrease crevice corrosion and help keep everything together without movement until a torch is applied to remove prop. Is this thinking out of the box or is it too far out?

 

[Lou_tribal]

Well if you seek to keep everything together I would rather go with Loctite as it is intended for this. Not sure about its usage on a prop nut though but they have product for almost any environment so I would not be surprised to see one for marine usage.

 

[Bacchus]

Ok is this a dumb question? Why not epoxy the whole thing together. Do the proper fit including key and then use epoxy on prop key and nuts. This should keep water out and decrease crevice corrosion and help keep everything together without movement until a torch is applied to remove prop. Is this thinking out of the box or is it too far out?

That's along the line that Seaboard recommends... at least re: the nut - he uses 5200 which in my mind is similar - heat req'd to be break loose.
Get a key that fits reasonably well and the most important part is to make sure the taper fits very well - lapping is the most important part of everything noted... do that and keeping a prop tight is easy.

many folks believe the key does the work holding prop / shaft aligned when in fact the taper is what does the majority of the work.

MANY Lathe & Drill press chucks have tapers and NO keys and NO nuts to hold them in place - if the taper is a good fit it doesn't move

 

[RT Firefly]

Greetings,
Mr. Ski. I'm with you on 99%+ of your posts but..."And I don't see a big issue with using a pipe wrench on the nuts. A bit of rash on the flats??" Aaahhhhhh!!!! Not hard to find a tool that fits properly.

 

[BruceK]

Some thoughts for the engineers:
Would a castellated nut work?
Would wiring the nut work?
Would lining up the gaps to insert the lock pin inhibit correctly tightening the nut?
Would a pin hole weaken the shaft?

 

[Northern Spy]

Some thoughts for the engineers:
Would a castellated nut work?
Would wiring the nut work?
Would lining up the gaps to insert the lock pin inhibit correctly tightening the nut?
Would a pin hole weaken the shaft?

That's what I do.

Mainly because my zinc type.

Shafts designed to the standard have a hole for a cotter.

But I'm not a P.Eng either... [emoji3]

 

[cardude01]

Got the prop cleaned and back on. Tightened the hell out of it with a pipe wrench. Everything seems tight.

I'm getting the hell out of here before I break something!

 

[BruceK]

Got the prop cleaned and back on. Tightened the hell out of it with a pipe wrench. Everything seems tight.

I'm getting the hell out of here before I break something!

Someone will be pleased your shaft and nuts are back in order.

 

[cardude01]

That's along the line that Seaboard recommends... at least re: the nut - he uses 5200 which in my mind is similar - heat req'd to be break loose.

Get a key that fits reasonably well and the most important part is to make sure the taper fits very well - lapping is the most important part of everything noted... do that and keeping a prop tight is easy.



many folks believe the key does the work holding prop / shaft aligned when in fact the taper is what does the majority of the work.



MANY Lathe & Drill press chucks have tapers and NO keys and NO nuts to hold them in place - if the taper is a good fit it doesn't move

If you put 5200 on the threads, how would you service it, if you had to, while it was in the water?

 

[Lou_tribal]

Someone will be pleased your shaft and nuts are back in order.

Especially that now they are not backward anymore and that without any surgery!

 

[Bacchus]

Some thoughts for the engineers:
Would a castellated nut work?
Not a good solution if you have to "back off" the nut to align w pin

Would wiring the nut work?
That's "seizing" and what Seaboard recommends - I did mine this way and it hasn't moved in 4 Yrs

Would lining up the gaps to insert the lock pin inhibit correctly tightening the nut?
Not sure what you mean but it may be what I mention above??

Would a pin hole weaken the shaft?
Technically Yes - but - the pin (or seizing) hole is beyond the threads where the load is on the shaft
Shaft failures are frequently and the front end of the keyway... when the prop slip the load shifts to the key / keyway

...

 

[Bacchus]

If you put 5200 on the threads, how would you service it, if you had to, while it was in the water?

My boating world is in an area where annual haul out is the norm - not an issue even if a short haul is req'd.
I'm not used to divers etc doing things like props...

I realize there is another world - jusT not mine

 

[fstbttms]

Some thoughts for the engineers:
Would a castellated nut work?

Yes. This is not an uncommon arrangement.

 

[rwidman]

That's along the line that Seaboard recommends... at least re: the nut - he uses 5200 which in my mind is similar - heat req'd to be break loose..............

That makes it pretty hard to change the prop in the water. I don't think it's a good idea.

 

[Nomad Willy]

What's the spin on using NeverSieze?

On the taper.

I've had trouble getting props off in the past and thought about it but now that I use a MAP gas torch (hotter) getting the prop off is'nt a problem.

 

[Comodave]

You don't want to put Never Sieze or lubricants on the shaft since it will inhibit the prop from seating fully on the shaft. Do the lapping and then put the large nut on and tighten the prop fully. Then remove the large nut and install the small nut and then the large nut last. Using the large nut to draw the prop onto the shaft has more threads in contact with the shaft and won't strip as easily. But you do want the large nut on last since it will unload the small nut somewhat. If the small nut is on last you won't have as many threads holding the load.

 

[kchace]

You don't want to put Never Sieze or lubricants on the shaft since it will inhibit the prop from seating fully on the shaft. Do the lapping and then put the large nut on and tighten the prop fully. Then remove the large nut and install the small nut and then the large nut last. Using the large nut to draw the prop onto the shaft has more threads in contact with the shaft and won't strip as easily. But you do want the large nut on last since it will unload the small nut somewhat. If the small nut is on last you won't have as many threads holding the load.

This is what I was taught also.

?

 

[Northern Spy]

The actual standard calls for a surface finish of 60 microinches (funny number, usually 64). If you were putting together a taper with that finish, there is plenty of room to displace a thin layer of lubricant, which may allow it to ride higher on the taper. Once you lap the two surfaces though, using a fine grit, the surface roughness will be more like 4 microinches. I can't find my comparator gauge, so this is a guess. Lubricant on the lapped surface may be detrimental to the fit.

Honestly, I think this is a lot of overkill for something that really doesn't see massive amounts of torque anyways. Worst case scenario is shifting forward reverse gear quickly.

Also, anytime I request a thin layer of antisieze on a surface, I always put a hold point on it, as it often defaults to a "more is better mentality" and I end up taking most of it off, particularly if it is molybdenum disulfide based.

 

[Northern Spy]

The only reason, I lapped mine is because I repowered and repropped. Either my shaft or prop taper was off when I blued it. I honestly don't remember if I used antisieze or not; I doubt it though. Probably a light machine oil.

 

[fstbttms]

What's the spin on using NeverSieze?

On the taper.

I've had trouble getting props off in the past and thought about it but now that I use a MAP gas torch (hotter) getting the prop off is'nt a problem.

As previously mentioned, the mechanical connection between your prop and shaft is not designed to have anything in between it, be it some sort of lubricant or some sort of adhesive. The prop is not supposed to come off easily. That's the whole point of the taper.