How do I remove these? Cap shroud mast-fixings

As i suggested - a tube with shouldered ends
This can be made fairly easily on a lathe & with a sturdy bolt through the middle to tighten on a couple of shaped mandrels to form the rivetted ends it can be re made easily if you have salvaged the tangs
Having a lathe I would make one for myself but would be a bit cautious doing it for someone else. I would need to source an aluminium tube of correct grade & dimension to allow the centre to be bored out to correct diameter If the ends had walls that were too thick they would not bell over correctly. Might need a bit of hammer work to get nice rivetted ends
I do have a supply of 19mm OD tube from the curtain walling industry. Walls about 3mm th from memory

If you sent me an acurately dimensioned sketch I would have a go just for the hell of it. If I do manage it ( assuming my ally is suitable size) you could have it for nothing. PM me if you like
I live near Bradwell
 
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Daydream believer said:
As i suggested - a tube with shouldered ends
This can be made fairly easily on a lathe & with a sturdy bolt through the middle to tighten on a couple of shaped mandrels to form the rivetted ends it can be re made easily if you have salvaged the tangs
Having a lathe I would make one for myself but would be a bit cautious doing it for someone else. I would need to source an aluminium tube of correct grade & dimension to allow the centre to be bored out to correct diameter If the ends had walls that were too thick they would not bell over correctly. Might need a bit of hammer work to get nice rivetted ends
I do have a supply of 19mm OD tube from the curtain walling industry. Walls about 3mm th from memory

If you sent me an acurately dimensioned sketch I would have a go just for the hell of it. If I do manage it ( assuming my ally is suitable size) you could have it for nothing. PM me if you like
I live near Bradwell
Click to expand...

I am no engineer, so I bow to your greater knowledge - and take your word for it !!

The season is a way off yet (understatement !!) so what I'll do is to think about it for a day or two then if I can't get it done in Inverness by my usual metal-man I'll PM you. I could send you all the bits.

Many thanks.
 
So in the interests of perhaps continuing to show my numptiness - how was th tube with shouldered ends first installed..?? There's a shoulder either end - is one (both??) of the shoulders supposed to be removable/adjustable so the tube can slide through the mast?? Some other way??
 
...I know that - what I'm struggling with is how the two shoulders holding the compression tube are fitted... does that tube come in two parts that just slide together with a shoulder each side, then the bolt to hold the lot together????
 
Fantasie 19 said:
...I know that - what I'm struggling with is how the two shoulders holding the compression tube are fitted... does that tube come in two parts that just slide together with a shoulder each side, then the bolt to hold the lot together????
Click to expand...

My assembly is well-and-truly-corroded and I found impossible to remove the two outside "end caps". These, I assume were originally fitted over the ends of the compression tube after that tube had been placed inside the mast (obviously with something through it to stop said tube disappearing into the spar!!).
The end caps have a wider "face" diameter than the tube, so not only hold the tube in place, but also accept the threaded-at-both-ends bar through the tangs and plate and the final nuts (which were burred-over to prevent unscrewing).

I forgive your numptiness, I was at that stage only a day ago;)

P.S. See Parsifal's thread above # 31
 
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The 2 shoulders on the tube should be exactly the same distance apart as the thickness of the mast
The 2 shoulders are meant to hold the tangs apart to prevent mast compression
If the ends were not belled over then the tube may have been threaded to take 2 external retaining discs to hold the tangs on or they may have just been an interference fit. I would imagine that that would be reinforced by a bolt through the middle of the whole assembly to prevent tangs pulling off.
 
Daydream believer said:
The 2 shoulders on the tube should be exactly the same distance apart as the thickness of the mast
The 2 shoulders are meant to hold the tangs apart to prevent mast compression
If the ends were not belled over then the tube may have been threaded to take 2 external retaining discs to hold the tangs on or they may have just been an interference fit. I would imagine that that would be reinforced by a bolt through the middle of the whole assembly to prevent tangs pulling off.
Click to expand...

Correct. And if you take a closer look at that bolt/bar you can see that the wire halyard has ground through to about a third of its thickness.
I wonder how long I had before failure and ensuing disaster.
BUT, on my assembly the "shoulders" are what I describe as the end-caps, which are (were) pushed over the compression tube. The tube is just a straight item which fits exactly through the hole in the mast.

NB, folks:-
Wire halyards may be good for reducing stretch, but consider how many "time-bombs" are bobbing around our seas :eek: ?
 
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Y
Daydream believer said:
The 2 shoulders on the tube should be exactly the same distance apart as the thickness of the mast
The 2 shoulders are meant to hold the tangs apart to prevent mast compression
If the ends were not belled over then the tube may have been threaded to take 2 external retaining discs to hold the tangs on or they may have just been an interference fit. I would imagine that that would be reinforced by a bolt through the middle of the whole assembly to prevent tangs pulling off.
Click to expand...
The compression tube, as it's name indicates, is to withstand the compressive force exerted when the nuts are tightened, so as to prevent the mast being crushed.

The turned down portion of the compression tube only needs to be a close fit in the s/s collars. There is no need for it to be threaded or riveted over ("belled over"). The through-bolt, or stud in this case, and the five pop rivets are sufficient to keep everything in place.
 
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parsifal said:
Y
The compression tube, as it's name indicates, is to withstand the compressive force exerted when the nuts are tightened, so as to prevent the mast being crushed.

The turned down portion of the compression tube only needs to be a close fit in the s/s collars. There is no need for it to be threaded or riveted over ("belled over"). The through-bolt, or stud in this case, and the five pop rivets are sufficient to keep everything in place.
Click to expand...

Correct.
But in my case the tube is alloy and the collars, as you say, are s/s. The main problem I had with removal was that the "bi-metal corrosion" was so bad I could not remove the s/s collars.
I suppose annual removal, cleaning (and greasing?) would be a good item to put on the Autumn Maintenance List?
 
U
Robert Wilson said:
Correct.
But in my case the tube is alloy and the collars, as you say, are s/s. The main problem I had with removal was that the "bi-metal corrosion" was so bad I could not remove the s/s collars.
I suppose annual removal, cleaning (and greasing?) would be a good item to put on the Autumn Maintenance List?
Click to expand...
Blimey! That would be taking maintenance to extremes. Better to apply some Duralac, or similar, in case you ever need to dismantle it again in your lifetime.:D
 
NormanS said:
The main thing now is to lead the halliard the correct side of the new tube/bolt.
Click to expand...

Agreed, but I think the wire halyard will be ditched in favour of a Dyneema one.
Annoyingly, I fitted a brand new Dyneema main-halyard two years ago and shredded it (on that through fitting) so I reverted to a brand-new wire halyard - which may now be surplus to requirements.

Anyone interested? - sensible price.(Fits 33' mast. head-deck) Eye+thimble one end and long rope (polyester?) tail. Only been used two seasons, one locally - minimal use - and the second as a topping lift - virtually no use.
 
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Exciting follow-up folks !! ;)

After boiling and cooling the through-mast fitting yesterday, for about four hours, then punching away through the tube at the cap, I gave up and ground the wretched thing out.

So, now we see the s/s cap, of which I shall have to make one, probably two replacements and the compression tube - which I think needs needs replacing........

I'm going to try my local metal-man first, but if any of you have any ideas where I might be able to buy standard bits, please do tell.
If all fails then I shall contact those kind folk who have offered to tool items.

Just as I was going to sleep last night I had a disturbing thought - will there be a spreader through-fitting in similar or worse condition?
Another we job on the list.
Hey ho!

Should have shown the other end of the tube, showing how I ground out the cap. Doh!
 
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If you're not keen on getting an engineering firm to do it, why not try and make contact with your nearest model engineering club?

The average m.e. would have no problem turning up the bits you need and it might cost you no more than a bottle of scotch.



Have you the same damage to the compression tube at the spreaders?

Probably not. Because that at the mast head has had the wire halyard bearing heavily on it, being nearer the sheave. But as you have the mast down it's a good opportunity to check everything.
 
parsifal said:
If you're not keen on getting an engineering firm to do it, why not try and make contact with your nearest model engineering club?

The average m.e. would have no problem turning up the bits you need and it might cost you no more than a bottle of scotch.



Have you the same damage to the compression tube at the spreaders?

Probably not. Because that at the mast head has had the wire halyard bearing heavily on it, being nearer the sheave. But as you have the mast down it's a good opportunity to check everything.
Click to expand...

After I finish my cup of coffee I am going out to the mast to examine the spreaders.
Watch this space!!

Good thinking about m.e. clubs, but we don't have many (any??) up here!
My nearest engineering facility will be Inverness, where I'm going anyway next week.
 
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