Swaging questions

[Brion Toss]

Hello,
Oh, dear. As far as I know, only Wire Technic (sp?) swages are suited for single-pass swaging; standard Kearneys specifically require two passes, with the second 90? to the first. Yes, this makes for fatigue, but one pass simply doesn't compress enough metal far enough. Make two passes ó and no more than that, or fatigue happens in a bigger way ó unless the machine manufacturer says otherwise.
We see far fewer fatigue problems with rotaries, and the ones we do see are often from machines that have gotten out of spec. This seems to happen rarely with rotaries, and I can only speculate that this is because the much more expensive machine tends to end up with much more careful people. Kind of like being more likely to attend to oil changes with a Rolls than with a Yugo.
Fair leads,
Brion Toss

[Brian Duff]

Ok, great, I had a feeling I had been doing it right. I suppose I should have thought to double check the manufacture (of machine) instructions, but they are filed away up in the office somewhere, so thanks for the clarification.
We have a couple of kerny swagers, and a Wire Technik too, I was un aware that the Technik only required one pass, I will double check the instructions and make sure.
Thanks for the clairification.
oh, and I kno a rotorary swager is better, but like brion mentioned, they are expensive, and our shop doesn't have one. actually only one of the dozen or so riggers in Annapolis has a rotorary swager. they are not very common...

Feeling like a better rigger already...

[Russ L]

Hi Brion,
Opinions should always be packaged with a caveat. Yes, the one pass machine is the Wireteknic. Are people still using "banana swage" machines? I supposed they are okay with a good operator.
What is your opinion on the net result of a swaged fitting when the second pass expands the outside dimension of the first pass?... even slightly.
Cheers, Russ L

[Brian Duff]

Russ L.
What machine do you use in your shop to swage 'swage insulators' commonly requested by owners for using thier backstay as a radio antenna?
the only tool we have to do that is a Kerny swager, as they cannot be pulled by the WireTeknic . I suppose that is the only reason to use a 'bannana swage' machine.
Oh , and for making vinyl coverd lifelines, which I dont like but were standard for many years and still preferred by many owners ?

Hoping to learn a new trick or tool from this,
Brian

[Russ L]

Hi Brian,
No shop... I'm just an old hand. A couple o' decades ago they would have called me a "ship's husband" now they just call me opinionated.
I recently (last year) stepped away from the 36 ton cutter I fitted out over the course of 16 years and now I'm happily sailing a 7 ton classic plastic yacht.
I would use reuseable insulators, such as StaLok, in the backstay. They are expensive intially but cheaper over the long haul.
I too am not a fan of wire lifelines. The best liferail I made was sch 40 pipe welded atop S/S tapered stanchions... unfortunately that doesn't scale down to smaller boats (and still look good).
Cheers, Russ

I too heard that applying goop into the swage before swaging weakens the overall strength of the assembly. Swages rely on metal to metal contact for their strength so applying goop before swaging would be comparable to adding WD-40 to Super Glue. Regardless, in most cases, this is a non issue because the safe working load allows for the reduction of strength due to the goop.

Thinking of swaging machines and the notion that two passes on a roller swage causes too much fatigue, I ask what makes a rotary swage machine any better than the rest if it beats the crap out of the swage fitting? I've seen some swages that were formed with a rotary and the stainless had been worked so much that it changed to a darker color. Sure, theyíre smooth, but also work hardened. Again, this is a non issue because of applied safe working load

[Brion Toss]

Hi Brian,
Most Kearney-type swagers need to be turned 90? for the second pass, according to their manufacturers. The dies prevent the second pass from undoing the compression of the first pass, but as I understand it, fatigue from the radical distortion of metal is much more of a problem than with rotary swages, which bring the metal down in smaller, smoother increments.
There will still be a ridge showing, with a Kearney-type machine, even if you turn it 90?, unless either the machine or the operator has some trick way of preventing or minimizing this (in other words, to try to make it look like a rotary swage).
What you might be seeing from Selden is the product of a WireTecnic (sp?) machine, which leaves a very pronounced ridge, almost a fin, on either side. And with these machines, one is instructed not to make a second pass. The back story here is that the WireTecnic machine, unlike its cousins, pulls the swage along by its end; every other Kearney-type machine powers the dies. The idea is that, with unpowered dies, one can get less deformation in the machine ó the metal of the swage compresses more at its own rate, with a constant pull, instead of being forced through at the rate set by gearing. Or that's how I understand it. These swages have a very good rep in Europe, where they originated, but haven't much caught on here yet. This might in part be due to their appearance, which isn't smooth like we're used to. Some shops will grind off the flashing, which strike me as a bad idea for at least a couple of reasons, and which adds noise, hassle, and time to the swaging process. And one outfit in Seattle still, as far as I know, makes repeated passes with their WireTecnic, to eliminate the flashing. When I suggested that this might be a time-consuming way to accelerate metal fatigue, the machine operator said that his manager, who was an engineer, said that's the way to do it. An engineer. Right.
Fair leads,
Brion Toss