Mystery pre-war tandem brazings - any ideas?

[XCDave]

My dad and I bought an unknown pre-war tandem frameset before lockdown in tasteful dog-poo brown and are finally getting round to doing something with it. I've been lost in a world of lugs and whatnot trying to see if we can find out what it is, but none of the usual mainstream suspects (BSA, Hercules, Sun, etc.) seemed to offer anything which has everything this does, so we've decided it was a custom one-off and are no longer bothered about what it is.
However, it has some interesting brazings on both the front and rear fork legs, which look like they might be something to do with brakes but I'm not sure what. I've had a delve into the world of non-mainstream pre-war brake oddities but have now admitted I'm out of my depth. The curiosity remains though, so... does anyone know what these might be for?




They're both the same distance above the rims. I found some French brakes which used similar brazings but at a 90 degree angle to how these are positioned (can't remember the name of them now), but frame has English bb threads and English sized wheels (26 x 1 3/8 ).
Any help welcomed, it's unlikely we'll use them as we're going for drum brakes but I'm itching to know what they're for!

 

[XCDave]

Some other pictures of frame if anyone is interested.



Looks like this eyelet has literally been screwed into the frame:

 

[grantoury]

Really nice frame. I can't help you with those braze ons, though

 

[Guinessisgoodforyou]

@keithglos should know. They look like mudguard braze ons but too far up.

 

[Old Ned]

Rack supports?

 

[Jonny69]

They look like rack mounts to me, too. I can't think of any brakes that mounted on fittings like that. There's a good chance it would have had Resilion brakes, which clamp round the fork legs below where those fittings are. If it didn't have Resilion brakes, it probably would have had BSA calipers or hub brakes.

 

[XCDave]

Thanks all for your replies.
Had wondered about rack/mudguard mounts but they just seem to be too high up for either.
Jeay were the brakes I had found, remembered them - they used lugs in a similar position to these but were more like a BMX U-brake mount.
Guinessisgoodforyou, I'll wait see if keithglos comes up with anything, thanks!

 

[Nabeaquam]

BB appears to be the type that can be moved to adjust chain tension. The headset appears to be even earlier than the 1930s BSA type. Could be from the 1920s, or even older. I have a late 20s bicycle with an almost identical headset. The tabs are strange. The frame and fork are drilled for a brake mount bolt. The slots in the tabs appear to allow for a brake to be adjusted up and down. Perhaps their for a brake like the old Phillips that clamp onto the stays and fork legs. Perhaps it’s the same system but the tabs allow a direct mount. The holes in the frame and fork could be added later or original to allow different brake systems to be mounted. I have seen parcel racks that mount on the fork and stays but the tab position on your frame looks like a rack would interfere with a frame mounted brake. It’s a mystery for sure. I’m putting my guess on that they are for mounting brakes. Same distance above the wheel rim sort of cements this notion in my brain.

 

[XCDave]

Thanks for the reply, more food for thought! Headset's a curious one as it definitely has that late 20s/early 30s look to it, but actually takes 1 1/8 quill size. Presume this is an early 'oversized' thing for tandem use, which was then rediscovered/recycled (as so much 'new' tech is) into the 90s headtube standard. Am quite enjoying taking on something new and all the random new knowledge you stumble on in the process!
I'm sure the tabs have something to do with brakes like you, but am beginning to think I'll never get to the bottom of it.

 

[Midlife]

Resilion brakes sprung to mind but not sure they were braze on just bands?