More on the Douglas / Chater-Lea connection

[cardan]

I'm not a great student of Douglas history, but the story goes that before Douglas-branded hubs came in around 1913, Douglas used hubs from Chater Lea. Given the similarity in design, my best guess is that "Douglas" hubs were either built for Douglas by Chater Lea, or built at Douglas under license from Chater Lea.

At the moment I'm building up a 1904 Chater Lea FN (i.e. an early FN motor in a frame set built by Chater Lea specially for the motor). In the parts bin I found a pair of Chater Lea "pull backs" for the rear axle - squared off at one end so more like 1910 than 1904 (round). I'll use them on my bike.

Here's the Douglas connection: the threads on my pull backs are that old Douglas favourite 17/64" 25 tpi. I'd expect the ordinary CL version to be 1/4-26, or at the outside 17/64-26 (which was a cycle thread used mostly on cotter pins).

Does anyone have a very original Model A Douglas? Does it use 17/64-25 pull backs?

I think all later Douglases had non-adjustable rear axles.

Cheers

Leon

[TonyC]

Hi Leon,

The 1907 Douglas has this method of adjustment so will take some pictures and put them on the Forum.

Tony

[TonyC]

Hi Leon,

Attached are some images

Cheers

Tony

[Chris54]

Hi Leon,Tony
Very interesting pictures, i recently purchased an early bike, believed to be a 1904 Chater-Lea with a Fafnir engine (auto inlet),
what cought my eye is the rear stand, mine has the same stand, never seen one before, it it as old as the rest of the bike.
Leon, would be interested to see some pictures of your Chater-Lea, i will find mine and post them, perhaps start a thread in the Kingswood Pub as not entirely Douglas related.

Chris

[cardan]

Thanks Tony and Chris,

Yes this is the wheel adjusting setup, no doubt the Douglas origin of my Chater-Lea-like 17/64-25 axle pull backs. I have no idea where I got them from, but they're the sort of things I would pick up at a swap meet / autojumble for my bits and pieces collection.

The rear stand on the Model A in Tony's photo is an aftermarket device called the Ukantes. It was popular for a few years from 1907. Most makers fitted stands to bikes as original equipment from about 1910.

Happy to discuss Chater Lea stuff Chris - let's do it "in the pub".

Cheers

Leon

[cardan]

Re the 17/64 - 25 tpi "Douglas" thread.

I've been fiddling with Chater Lea chainwheels (pedal sprockets), and it turns out that Chater Lea used 17/64-25 hex-head screws to attach their chainwheels to their crank arms.

I wonder if I'm barking up the wrong tree re the 17/64-25 thread originating with Douglas. Perhaps Douglas inherited the (ridiculous) 17/64-25 thread from Chater Lea, who supplied them with cycle fittings (e.g. hubs) for their early machines?

The "Industry Standard" at the time was the CEI (Cycle Engineers' Institute) set of threads, which included 17/64-26 (not 25), mostly used for cotter pins.

Sad that I think about such things, isn't it. I'll try to put it behind me and move on...

Leon

[cardan]

I'll try to put it behind me and move on...

Nope...

Fitting a pre-1910 Chater Lea belt rim brake to a (non Douglas) bike today, the threads for the two screws that clamp the mechanism to the chain stay are both 17/64-25, as is the threaded hole in the shoe where the operating arm attaches.

Lovely that the original screws are still there, with the rarely-used 1/8 Whitworth hexagon.

Mark down 17/64-25 as a Chater Lea proprietary thread that was enthusiastically adopted by Douglas.

Leon