Different swages, different rotations
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
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