Has anyone else had trouble with these couplings breaking at the double bend as they come out of the NEM pocket? I put a foam rubber cover over the top of the coupling to protect it when I put the loco in my stock box but I have had several couplings sheer off. They quite often need adjustment to the height when I get the loco out and then break off at the bend. They need some sort of reinforcement at the bend
I have heard of issues with the couplings breaking at the bends at they are being made, but that may have been due to the wrong sort of brass being put into the process by the etchers ('hard' sheet rather than annealed) as an odd 'rogue batch', or by the builder 'getting it wrong' and trying to bend things back to the flat to try again.
From what you describe - the coupling breaking at the bend and that you have been bending them to adjust the height - I wonder if the failure is use to the metal work hardening at the bend and becoming brittle.
You could modify the couplings by adding reinforcement (soldering on a brass strip to reinforce the point they are breaking at once you've made them?), but my suggestion would be to rethink the way you pack the locos so that there is no pressure on the couplings in transit, even from a foam rubber cover as this is still transmitting a force onto the couplings, to avoiding bending them in transit. Remember loco are often heavy things, so the couplings may be taking quite a bit of force.
That should eliminate the need to keep adjusting them, and without the adjustments there would be no work hardening of the metal, and therefore no breaking.
I have had the work hardening issue too when making couplings up. You really only get one chance and re-bending and even adjustment has ended in failure for me. Also after a bit I avoided making the bends too sharp.
My stock are still the old painted or coated version and I understand they are now bare - which is good because I started stripping and reinforcing with a touch of solder.
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Over the years I have used Greenwich couplings on my three "O9" exhibition layouts. Whilst a little fiddly to assemble I found them worth the effort and reasonably robust. I never had any breakages.
More recently I wanted to fit them to some "OO9" rolling stock and tried the version intended for use with NEM pockets. Despite my previous successful experience I broke several.
My enthusiasm for the Greenwich coupling is undiminished, but for future installation in NEM pockets I will use the original type with a styrene shim and glue as necessary.
CP
Some useful suggestions to try. Thank you