EK Ring Soldering

[Ammersee]

On some EK2's, the small ring is only soldered to the frame on one side. Is this trait only on '39 crosses or is it on some '14 crosses as well?

On the unsoldered side, is there a small gap between the ring and frame or is the ring in contact with the frame?

I have an idea why this was done but would like to see a pic of one before I stick my neck out with my theory. Anyone have a close pic? Ammersee

[streptile]

From elsewhere on the forum:

[Ammersee]

Thanks Trevor, nice pic. Here's my idea. I think the ring was soldered to the frame before the two halves were soldered together. The gap allowed the two halves to be joined even though the ring was in place.

When you buy silver solder it comes in 3 different melting temps. They call them "hard, medium, and easy". It comes this way so you can assemble multiple parts without disturbing the previous solder joint. You would use the "hard" solder (hottest melting temp) to join the first two parts, then "medium" to join the next part. The "hard" solder joint would not be disturbed by the lower temp of the "medium" joint.

If the frames are joined first the ring would have to be soldered using a lower temp solder which would have less strength. If the ring was soldered first, using "hard" solder, the frames could be joined using a lower temp solder which is also much easier to use than the "hard".

I would only be correct in this if: A "hard" soldered ring on one side only has more strength than a ring "easy" soldered on both sides. I'm guessing that it would. The "hard" silver solder I have is 65% silver, takes high heat (acetylene) to melt and has incredible strength. Maybe in the case of the one-sided soldered ring, "less is better". Unfortunately it would be impossible (or very expensive) to test my hypothesis.

Having the 3 "strengths" of solder would also be very useful when assembling an EK1. First, the block and tubing would be "hard" soldered together to form the hinge. The tube on the hinge end of the pin and the hook could also be "hard" soldered. The hinge sub-assembly would then be soldered to the back plate with "medium" before the halves were joined. The back plate could then be soldered to the front with "easy" without disturbing the hinge/pin system or the hook. Ammersee

[gregM]

On some EK2's, the small ring is only soldered to the frame on one side. Is this trait only on '39 crosses or is it on some '14 crosses as well?

Also seen on "Type A" 1870s.

[Roglebk]

A very sound theory! When looking at items from the burned C F Zimmermann factory horde one can actually draw the same conclusion. The solder of the halves were the first to melt and has run onto the back and sides of several different crosses. Some are of course worse than others, the heat from a fire is not even, but so far i saw no crosses with lost jumprings, screwbacks nor pins/hinges from the horde.

[streptile]

Very interesting theory, Gary. I think it's probably very likely accurate -- it just makes a lot of sense.

Of course most EK2s have jumprings that are soldered on both sides, meaning (if we follow your line of thought) that the jumpring would have probably been soldered on with "medium" after the frame halves were joined with "hard." I think this would make some sense, too.

Thanks for sharing the idea -- it's fun to figure this stuff out.