Help identifying block/sheave pin

Matwill

Matwill

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Hi Guys,

I have 2 of these blocks at the base of the mast, one of them is missing a bit that holds the pin in place, any help identifying the maker or a replacement pin would be great

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I'm sure Selden will sell you one. But make sure you're sitting down when they tell you the price.

It's probably a bog standard pin size though, so well worth checking chandlers (probably won't be hollow though). Or put the sizes up on here, most of us have a load of spares that don't quite fit what they were bought for.
 
Look at this thread, Post 28

Custom made block

You don't show the 'inside' of the clevis pin you have - my guess is it is threaded on the inside and is the female portion of a sex bolt, like those I illustrate.

You may not be able to match what you have but will be able to find a supplier of sex bolts.

If it is threaded find your self some metric and imperial bolts of the approximate size until you find one that matches the thread. You want a bolt that completely fills the female - so the male portion wants to thread right to the end of the female section. So if you find a match buy an oversize (long) version and then cut it back to fit. My guess is the assembly is stainless, 316 - that's a good place to start.

Someone here will tell you if you need some thing better than 316, if its duplex stainless try Petersens in Newcastle.

If its threaded you are home a dry, any bolt strong enough of the right thread and same metal is just what you want, identify each of those of the unknowns - easy - will keep you busy in a hardware store for an hour or so - and again if I ma right - as cheap as chips

I'm interested - lets us know the answer (or that I am barking up the wrong tree!)

Sorry - forgot to mention - you will need to take the sheave 'off', remove what I call the female portion and take it with you to match. Stick a screwdriver in to retain the sheave in place whilst you are doing your Sherlock Holmes bit.

Jonathan
 
Neeves said:
Look at this thread, Post 28

Custom made block

You don't show the 'inside' of the clevis pin you have - my guess is it is threaded on the inside and is the female portion of a sex bolt, like those I illustrate.

You may not be able to match what you have but will be able to find a supplier of sex bolts.

If it is threaded find your self some metric and imperial bolts of the approximate size until you find one that matches the thread. You want a bolt that completely fills the female - so the male portion wants to thread right to the end of the female section. So if you find a match buy an oversize (long) version and then cut it back to fit. My guess is the assembly is stainless, 316 - that's a good place to start.

Someone here will tell you if you need some thing better than 316, if its duplex stainless try Petersens in Newcastle.

If its threaded you are home a dry, any bolt strong enough of the right thread and same metal is just what you want, identify each of those of the unknowns - easy - will keep you busy in a hardware store for an hour or so - and again if I ma right - as cheap as chips

I'm interested - lets us know the answer (or that I am barking up the wrong tree!)

Sorry - forgot to mention - you will need to take the sheave 'off', remove what I call the female portion and take it with you to match. Stick a screwdriver in to retain the sheave in place whilst you are doing your Sherlock Holmes bit.

Jonathan
Click to expand...


HI Neeves, its actually smooth on the inside and outside of the hollow part that is left in there - it looks like they just mated and thats all - ill just get solid ones and bin these
 
Its very difficult to believe they did not have something positive to hold the 2 parts together - but if that's it, that's it. Maybe they were held together with Loctite - and it failed eventually. I assume the other sheave blocks are secured the same way - I'd be inclined to at least check the others - and maybe replace.

A cheap fix would be a stainless nut and bolt, Alan keyed pan head, with a long unthreaded shank (fully threaded are called machine screws, I think) and just a short threaded portion for the nut. My guess is you would want a low profile nut. You might need to buy long and cut the threaded part back to suit.

Again I don't know if you need something with a bit more grunt, tensile strength, than 316 (possibly a duplex).

I'd try your hardware store first, it might be cheaper.

Secure with blue Loctite, red might be impossible (or very difficult to release without a blow torch)

Jonathan
 
As an update from yesterday - i went back down to the boat and took a better look with measurements, its indeed just a smooth hollow pin that has plastic end caps pushed in - of the 2 blocks i have only 1 of the plastic inserts has broken which is amazing after 40 years. The good news is because it is hollow i can get away with a 10mmx30mm clevis pin if i reuse the existing hollow pin, will probably need a teflon M10 washer on the outside to hold it in place

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Update No 2 - I managed to get out the old plastic insert with a bit of force and a drill, it was stuck in there surprisingly well,

I went with a longer clevis pin so I could add a nylon washer and stainless washer which are needed to cover the 16mm outer diameter of the hollow pin, the nylon should help with keeping the stainless and aluminum apart

When i first started looking at 20mm selden clevis pins i thought I wasnt going to get much change from 200 euro, but because i just needed 10mm pins both sides cost 10 euro including shipping, so i'm pretty happy

Now time to put in the new halyards

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