Trouble is , these things aren't looked at till they break. It's not easy to test their" condition". It's possible Drags haven't sold many. If you have a "chair" or race or ride fast you don't need a locked brake, which is what happens when this part fails. Nobody needs a locked brake and one caused my only "come off ever" on the road, where another vehicle wasn't involved to hit me.
This is the place where you adjust the brake on an Ariel if you are lucky enough to have a model that fits it and it is the main reason Ariel brakes work better than other similar age bikes + the cast drum which is better than steel always.. It's on rear brakes from about 38 and the front where tele forks are fitted. I 'm lucky I have a few spare (for ME, sorry) but I would even consider replacing them on any bike I have that has them. You could test yours with a small shifter on the edge of the wider round part by applying a reasonable force. If it does break you have maybe saved yourself an injury, but we better have a source before you start testing. THAT actually doesn't make sense but you know what I mean. Some of these may have been made from a better batch of potmetal which is what it was often referred to as.. You can't usually weld it either. It has zinc, aluminium and lead in it. It's really rubbish but casts well. The aluminium brake shoes are of GOOD metal. They don't dare make them of diemetal. Perhaps someone has, but they should then be tarred and feathered. Nev