Seal 22 Rudder Pivot Bolt.

[Floyd Raser]

Does anyone know the spec of the rudder pivot bolt for Seal 22 Sinbad?
The one I have removed is 3 inch by 1/2 inch with a 1.25 pitch. I am struggling to find the spec anywhere to order a new one.
I can find out next weekend but just asking here in case anyone knows.

 

[VicS]

Does anyone know the spec of the rudder pivot bolt for Seal 22 Sinbad?
The one I have removed is 3 inch by 1/2 inch with a 1.25 pitch. I am struggling to find the spec anywhere to order a new one.
I can find out next weekend but just asking here in case anyone knows.

3" long

½" diameter presumably

but what do you mean by 1.25 pitch? Cant be 1,25" or 1.25 tpi

Do you mean 0.125" pitch ie 8 tpi

8 tpi would correspond to 1" Whitworth, 1½" BSF, or 1" UNC ( or some much larger size I dont have listed UNF) So none of those if its only ½" diameter


1.25mm perhaps ???

which would correspond to M8 ( or M9)

or to M10, M12 or M14 fine,

Are you looking at 12mm diameter not ½" ?

 

[Floyd Raser]

Sorry, I realise the question may have been slightly misleading.
The only pitch gauge I have is metric so it is 1.25mm. Or at least, that's the best I can match it to. The shank measures 12.5mm and a 13mm drill won't go through the hole in the rudder stock. The boat is 1978 so I reckon it's 1/2 inch. I can't get to see my engineer mate until next weekend which is why I'm pitching (ouch!) the question here, in the hope that another Seal owner will have one.

I was let down by a usually very reliable supplier who measured the old bolt and declared it to be M12 but he didn't have one. I duly ordered the minimum quantity from Ebay, 2 bolts and 5 nuts, and they're wrong. I could re-use the old bolt which is only slightly worn but as I'm making a new blade it seems right to have a new pivot.

Thanks for the reply.

 

[VicS]

Sorry, I realise the question may have been slightly misleading.
The only pitch gauge I have is metric so it is 1.25mm. Or at least, that's the best I can match it to. The shank measures 12.5mm and a 13mm drill won't go through the hole in the rudder stock. The boat is 1978 so I reckon it's 1/2 inch. I can't get to see my engineer mate until next weekend which is why I'm pitching (ouch!) the question here, in the hope that another Seal owner will have one.

I was let down by a usually very reliable supplier who measured the old bolt and declared it to be M12 but he didn't have one. I duly ordered the minimum quantity from Ebay, 2 bolts and 5 nuts, and they're wrong. I could re-use the old bolt which is only slightly worn but as I'm making a new blade it seems right to have a new pivot.

Thanks for the reply.

sorry I've overlooked the bleedin obvious

I reckon therefore probably 1/2" UNF which has a pitch of 20 tpi which is 1,27mm...... you'd see that as 1.25mm on a metric thread gauge.

1/2" BSF is 16 tpi, You'd see that as approx 1.5mm on a metric gauge

Is it possible to drill every thing out to suit an M14 bolt and put this through with a self locking nut on the end ? Might be easier than finding a 1/2" unf bolt this side of the Atlantic

Or use a 1/2" whitworth or BSF bolt with a nut on the end ..... if you can find one.

I take it thats its stainless steel?

 

[Floyd Raser]

Thanks Vic, I reckon you're spot on with 1/2 UNF. Sounds about right for the age etc. I'll have a look around before I try drilling through the stainless bits on the rudder stock.

Yes the bolt is A4/316 whatever.

 

[Floyd Raser]

Glad tidings.
Peter Bentley of Paignton trading as Aruncas on Ebay supplied me with 1/2"UNF x 3" A2 stainless bolts and they're a perfect fit.
I say "they" but of course I only needed one but hey ho.

Thanks again Vic, you were ri.. no, I can't say it. Ok, you were right!