In my varied kit collection I have a few items of NER rolling stock from Medley Models/NER Days and it recently came to my attention via a fellow modeller that among other things the buffer heads in some of the kits need a little attention.
I had a vague recollection of Steve Hoyle mentioning something about his supplier having supplied them as they are and has subsequently passed away so no chance of doing anything about them.
These are what came with some of the kits (appologies for the slightly out of focus photos). You will note the interesting collar that would prevent any kind of compression…

I bought a couple of B1 opens from Mossy and they have been sat on my desk with the buffers beckoning to me each time I sat at my laptop. So this afternoon I decided to turn the collar off.
In the end I did about 30 and it was quite a good exercise in repeatability on the lathe using the graduations on the lead screw handwheels although the minor variations in sizes proved that they weren’t done with a CNC machine. I also took the opportunity to file off any centre pips and rub over the heads with emery while I had them in the chuck.