Andy_K 

OK, this may take some setup to convince you that there even is a problem to be solved here. If you use period-correct components, there's a good chance you haven't noticed. You are aware, no doubt, that British bikes, particularly Raleighs, had a few non-standard interfaces over the years. I'm going to make the claim that the cable stop on the chain stay is one such non-standard interface. You probably know the one I mean. It looks like this.



It's similar to the Campagnolo diver's helmet, but it has different dimensions. The step-down ferrule that fits into the Campagnolo diver's helmet flops around loosely in this one. The reason you may never have considered this to be a problem is that the flat ferrule often found on vintage steel coil cables fits this perfectly. So what's the problem? The problem arises when you want to use indexed shifting and modern 4mm cables. The modern cables are thinner than the steel coil, so that ferrule (which isn't easy to find to begin with) isn't what I want here. The ferrules designed for modern 4mm shift cables are to thick to fit the British half-dome cable stop. They butt against it and don't go inside. There are some ways around this, such as going without a ferrule (or even using the ferrule that fits the diver's helmet) and using a zip-tie to keep the cable in place to keep it from flopping around too much. But I've never been able to find a clean solution that I was happy with.

I've searched this forum many times trying to find a source for the right ferrule for this problem. I found a couple of threads where other people were asking for one, but mostly they had trouble communicating what the problem was. No solution was presented. I had pretty much given up. So much so that when I was sending my Mercian to @gugie for some modifications last year I had him replace the British cable stop with a standard diver's helmet.

Then last month all this changed. I was sending an old Zeus accessory to forum member @oneclick and he wanted to offer me something in return. I wasn't looking for anything, but he mentioned that he had a lathe and among the examples he mentioned of things he had done in the past was a step-down brake ferrule. It had never even occurred to me that ferrules could be made on a small scale. I described what I was looking for, and he agreed to give it a try. A short time later a packaged arrived in my mailbox with two ferrules -- one thin-walled straight ferrule, and one beefier step-down ferrule. Both fit the cable stop and the cable perfectly.

Well, I say perfectly... I was entirely satisfied, but when I sent a picture to oneclick he noticed a minor issue with the step-down version. He didn't have a bike with this cable stop on hand, and I had only guessed at the depth that would be needed for the step-down version. It turned out my guess was off by about two millimeters. Even like this the cable felt reasonable secure in the stop. It wouldn't move up, but you can see that it has a bit of room to wiggle.







oneclick suggested I should trim the end down to make it fit squarely against the cable stop. I grabbed a file and took it down a bit.





That looks better, but since I had it apart again, I decided to swap in the straight version of the ferrule. It's a bit more aesthetically pleasing anyway.







I'll post pictures of the complete bike when I can get it out in the sunlight (which, given that I'm in Oregon, may not be until spring). I have to say I'm very happy with this solution. Thank you, @oneclick! My grandchildren will sing songs of your greatness.

repechage

That stop was from the day where the cable housing was cut square, an awl to insure no hang ups and nothing else used.

Spaghetti Legs 

A flat file to the chainstay at the base of the stop would help the step down ferrule sit flush.


🧐

repechage

‘how about a file to the aluminum part? File through the chrome?

dddd

For those without a lathe, one way might be to get one of Shimano's aluminum step-down ferrules, which measure 4mm ID X 6mm OD, roughly.

Cut off the stepped-down part, then find a drill bit that fits snugly inside of the ferrule and turn (down) the OD against a file to match the ID of the stop.

On my 1971 Schwinn Supersport, the stops at the headset-mounted shift levers and the top tube weren't a good match to any ferrules fitting 4mm cables that I could readily find.
Over time though, I found some metal ferrules measuring 4mm ID and 5mm OD, and which fit everything pretty well (tightly but this was ok). These ferrules, usually found in black, seemed to be from some time in the 90's and not made by Shimano, based on the where and when of where they have turned up (I have since accumulated a couple of spares for possible future Schwinn projects.

I agree that housings exiting the stops at an abrupt angle is very bad for shifting performance, not only from unwanted contact of the cable against metal edge(s), but also from the elasticity that the sharp bend imparts on the cable as well as the cable housing yielding as it's endpoint rocks in response to changes in cable tension. It's an aesthetic issue as well.

Though time-consuming, dealing with such details is something I tend not to regret, much like adding plastic sleeve at the bottom bracket cable guide. Such sleeves, if well-sized, can even be installed after slitting and stay in place just fine, saving time/effort versus pulling the inner wire to install.

Aardwolf

Yep, before approx 1984 shift cables used 5mm outer.
Had the same issue with my 1982 Holdsworth Avanti until I realised it expected 5mm outer cut square and nothing else - brake outer worked fine.

Andy_K 

The full bike