Castle Nut

[LONG_KEELER]

On outboards, do propeller nuts have to be bronze ?

New ones are about £20 delivered. I would rather just use two stainless m8 nuts that are easy to fix and no
fiddling with split pins.

many Thanks

 

[RichardS]

I think my Suzuki prop nut is stainless so you don't need brass. However, I'm not sure why a castellated nut + split pin is so fiddly? How often are you actually removing your prop? I've removed mine once in 4 years so don't find the split pin particularly troublesome. It is definitely a better solution that locknuts, although a Nyloc with a locking nut will be fine if you really want to make the switch.

Richard

 

[Neeves]

I think my Suzuki prop nut is stainless so you don't need brass. However, I'm not sure why a castellated nut + split pin is so fiddly? How often are you actually removing your prop? I've removed mine once in 4 years so don't find the split pin particularly troublesome. It is definitely a better solution that locknuts, although a Nyloc with a locking nut will be fine if you really want to make the switch.

Richard

+1

And with a matching nut - if you are in a corner, you can make your own - with a hacksaw.

 

[LONG_KEELER]

Thanks for the responses .

The outboard is a Tohatsu 5hp 2 stroke 2006 .

I nipped out for m10 nyloc nuts and unfortunately could only make one revolution. Must be an imperial thread .

I do switch blades quite often. The skinny one and Mickey Mouse blades one .

Surprisingly, the broad blade prop does create lots more drag.

If anyone should know the thread type I would be most grateful.

 

[Lodesman77]

Have you measured the thread pitch?

Bolt Diameter (mm) 10
Standard Pitch (mm) 1.5
Fine Pitch (mm) 1.25

Alternately, is it specified in the manual?

 

[LONG_KEELER]

Thanks Lodesman !

Just measured the stud. As near as dammit , for a pensioner with vary-lens spectacles , 1.5mm space between threads. So sounds like I need
10mm bolt diameter 1.5 mm Standard Pitch.

The nut I bought which doesn't fit has stamped - A4-70 with a weird looking crest. Hard to measure but looks a wider pitch .

 

[Lodesman77]

A4-70 probably refers to A4 stainless steel, with 70 referring to tensile strength (not sure of the units)

If you're not certain of the measurement - to be sure measure ten threads, should be 15mm

 

[LONG_KEELER]

A4-70 probably refers to A4 stainless steel, with 70 referring to tensile strength (not sure of the units)

If you're not certain of the measurement - to be sure measure ten threads, should be 15mm

Thanks for the help.