PROBLEM, HOW TO - open up an inaccessible hole in 10mm s/s?

Irvine_himself said:
Unfortunately. not easily, they were rules of thumb that I learned as an apprentice in a general engineering workshop during the early seventies and, since it was a trade I eagerly gave up around 1978, I will most certainly bow to your greater knowledge.

I would say that however, from the point of view of the technical expertise of the people on this forum, that you missed some very important caveats from the BSSA article




I do not think I am being pedantic when I say that from the point of view of both DIY and in a lot of general purpose engineering workshops, the latter condition at least, would be fulfilled only co-incidentally. In other words, it would be welded with whatever electrode was available.

But, having said that, I freely and gracefully concede that my previous post was garbage.
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In your previous post the information you gave was for a butt joint.

Surely welding a chain link-or even a shackle without the pin-would not be butted, but positioned so as to give the largest surface area consistent with still being able to use the finished item as an attatchment-I would assume it possible to use at least half the length for a strong join.

My 2 pennyworth anyway.
 
rotrax said:
In your previous post the information you gave was for a butt joint.

Surely welding a chain link-or even a shackle without the pin-would not be butted, but positioned so as to give the largest surface area consistent with still being able to use the finished item as an attatchment-I would assume it possible to use at least half the length for a strong join.

My 2 pennyworth anyway.
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Having already been humbled, I will simply refer you to the linked BSSA article and point out that the joint you refer to is the fillet joint.
 
With the same stem head and the same problem when fitting a new furler, I got the closest SS bolt to fit - presumably 8mm in your case - and then sleeve the bolt with 2 sections of 1mm sidewall SS tube, each either side of the plate.

The chap whose advice is cutting speed, tool sharpness etc is absolutely right but, in a workshop. Hanging off the end of a bow, drilling through 10mm stainless steel plate, is so awkward that it's dangerous.
 
Irvine_himself said:
Having already been humbled,
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Not my intention at all. I suspect that your recollections may refer to ferritic/martensitic (400 series) stainless steel, rather than austenitic (300 series). Austenitics are never brittle, even at cryogenic temperatures of -170C. Ferritics could be, if the cooling rate was rapid, causing transformation of the weld and HAZ to martensite. Your description of tapping the weld is probably a known method of stress relief in heated components.
 
alahol2 said:
Terribly sorry old chap.

You will note that I enhanced the proposition by the insertion of 'high tensile' and by supplying a link to extra reading on the subject.
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You are quite correct of course and I misconstrued your helpful advice for the normal thoughtless postings that ignore previous posters' suggestions that we see elsewhere.
 
I reckon that with a short bit of a 10mm round file, with the end ground to fit a ratchet / socket, you'd have done it long ago.:D
 
Lakesailor said:
....but the resulting oval-ish hole will wear the pin through much more quickly.
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Why would it be oval-ish? I'm proposing rotating the file, and using it as a form of reamer, pushing it in using the side plate as a heel. Please note, you have to turn the file the correct way, or it will lock itself into the hole.
Even if it did turn out -ish, what difference would that make? It's a stationary pin in a stationary hole.
 
I have never managed to open a hole concentrically using a round file without doing it in a vice and with a good view of the workpiece.

A tapered slot, narrower at the top would bear on just two points of a round pin. Any movement, flexing, sideways, etc would wear the pin. Whilst you say stationary, it is a forestay.
Much better to use the smaller size pin, a good fit in the existing hole and, as suggested, sleeving the fork to fit the pin.
 
Lakesailor said:
I have never managed to open a hole concentrically using a round file without doing it in a vice and with a good view of the workpiece.

A tapered slot, narrower at the top would bear on just two points of a round pin. Any movement, flexing, sideways, etc would wear the pin. Whilst you say stationary, it is a forestay.
Much better to use the smaller size pin, a good fit in the existing hole and, as suggested, sleeving the fork to fit the pin.
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If, as you think, it would cause wear to the pin, how many years would it take this supposed wear, to reduce the strength of the pin down to the strength of the undersize pin that you propose using?
 
This could go on and on until someone tells us (a) how much weaker a 10 mil pin would be compared to an 11, and (b) how much force is the inner forestay going to excerpt. :confused:

PS. I still think 10 will be fine based on nothing more than knowing it'll take an awful lot to bend 10mm :nonchalance:
 
colhel said:
This could go on and on until someone tells us (a) how much weaker a 10 mil pin would be compared to an 11, and (b) how much force is the inner forestay going to excerpt. :confused:

PS. I still think 10 will be fine based on nothing more than knowing it'll take an awful lot to bend 10mm :nonchalance:
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Not to mention the dia of the wire it destined to hold up. No more than 8m/m is my bet
 
Irvine_himself said:
In this case, (drilling,) the real problem is not access, but the fact that inox is very hard and does not machine easily. In order to successfully drill, (or machine,) SS, you need a very, very slow cutting speed.
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Many years ago I had to open up - by a millimetre or two - the 3/4" holes for keelbolts in 1/4" stainless steel floors which I had just embedded in the floor of my Westerly. After some experiment I found that the best solution was a fluted tungsten carbide slot milling cutter in a die grinder (for those who don't know, that's an angle grinder without the angle). It worked a treat and cut the stainless like butter, though I got a bit enthusiastic and melded the braze holding the first cutter to its shank. Ping. After that I went more slowly, using coolant and frequent rests, and it all went just fine.

Unfortunately I don't think this would work for the OP because of the length of shank he'd need.
 
vyv_cox said:
Not my intention at all. I suspect that your recollections may refer to ferritic/martensitic (400 series) stainless steel, rather than austenitic (300 series). Austenitics are never brittle, even at cryogenic temperatures of -170C.
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Many years ago I earned my living doing cryogenic tensile testing of stainless steel / copper composites. Nothing fancy, just liquid nitrogen, but one reason we preferred stainless for that application was that it underwent a shear transition to martensite somewhere above 77K, giving a huge increase in cryogenic proof stress. I'm pretty sure that it was a standard austenitic stainless at room temperature.

Alas the funding ran out before I could get started on the really interesting bit, which would have been testing in LHe.
 
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NormanS said:
If, as you think, it would cause wear to the pin, how many years would it take this supposed wear, to reduce the strength of the pin down to the strength of the undersize pin that you propose using?
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Who can tell. Once flats have been started the pin is no longer free to rotate so wear will increase at a faster rate.
Who said the pin would be undersize? It is just not the same size as the hole in the yoke on the (inner) forestay.

Another thread shows wear on a forestay fitting. http://www.ybw.com/forums/showthread.php?382153-Elongated-hole-in-stem-head-fitting

Perhaps it's better to inspect every year instead of waiting for it to fail. That's how I see maintenance anyway.
 
Lakesailor said:
Who can tell. Once flats have been started the pin is no longer free to rotate so wear will increase at a faster rate.
Who said the pin would be undersize? It is just not the same size as the hole in the yoke on the (inner) forestay.

Another thread shows wear on a forestay fitting. http://www.ybw.com/forums/showthread.php?382153-Elongated-hole-in-stem-head-fitting


Perhaps it's better to inspect every year instead of waiting for it to fail. That's how I see maintenance anyway.
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Yes I saw the pic in that thread, and thought it should never have been allowed to get to that state.
 
Well, problem solved today and the easiest of all the possible solutions offered.......a high sheer stainless steel bolt off the

shelf that has the unthreaded shank exactly the right length to be in contact with all load bearing surfaces and a friction fit

in the existing hole and the jaw bar toggle attachment that the rigger supplied ..... :)

A great thanks to all, if nothing else I think it educated me a little more in the qualities of stainless steels and how to work

them and to ask the forum a long way in advance to get the best solution.

S.
 
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Sorry I havn't the parience to read all the answers so if this has been said forgive me. You will never get that hole cut out by hand. Even witha power drill if you can't get the drill pressure then you will just work harden the SS. A smaller pin has been suggested. If you don't like the los of strength. How much do you need ona temporary inner forestay for storm jib?
Extension plates from the existing hole have been suggested but that will leave you with 9mm pin or bolt as weakest point. However if rather than straight plates you can construct a triangle of SS plate of suitable thickness that will attach both to your 9mm hole and the hole further forward for the main forestay. This will give you 2 attachments one 9mm and one presumably larger that is used for the main forestay. The triangular plate then has a 10mm hole easily drilled in the workshop. Obviously this plate will have to be long enough in the base length to get the new forestay clear of the furler drum.
Having the pin to the inner foestay out in the open will make it easy to insert the pin presumably in the dark in a storm. So having the pin down inside the sideplates of the roller may not be such a good idea anyway. If indeed this is where you will attach it. good luck olewill or have I got it all wrong?
 
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