Douglasmotorcycles.net

In the course of making new brake hardware for the RA model, new front brake operating arm(s) needed to be made. These were based on an original sample, believed at the time to be RA.

Original sample
(https://www.douglasmotorcycles.net/aa-files/images/doug/2015/ra-front-brake/original-sample.jpg)


That turned out to be a wrong assumption as the arm is far too long for the brake cable anchorage on the front fork girder. This was readily apparent the first time the part was held up to a front fork, but unfortunately it was not visualized before. Also it was apparent in period photographs that the arm was short. Oh well.  :oops:

Long versus short brake operating arm.
(https://www.douglasmotorcycles.net/aa-files/images/doug/2015/ra-front-brake/short-verses-long.JPG)

New, shorter brake arms are in process, but the question is what model did the longer arm fit? Looking at pictures, the OB and CW seem to use a short arm similar (possibly the same) as the RA. It was suggested that the 4hp used a long brake arm, but I did not get to see an example of this myself. The ones I have seen have the veteran style forks with the stirrup brake. As far as I can see, use on any other model would have the same issue in that the arm would be too long for the cable anchorage. Any ideas?

The following images show the milling setup. Another fixture needs to be made to hold the part for surfacing the second side.

(https://www.douglasmotorcycles.net/aa-files/images/doug/2015/ra-front-brake/new-lever-1.JPG)

(https://www.douglasmotorcycles.net/aa-files/images/doug/2015/ra-front-brake/new-lever-2.JPG)


-Doug

Hi Doug

Rear brake lever for a CW perhaps? Or perhaps someone's attempt to provide more leverage to get the dummy belt rim brake to actually work!

Cheers,
Graeme

Doug..if of any help and from quickie eyeball measurements, my CW rear lever is about 3 ¼ in horizontally from the centre of the middle ½ in dia pivot hole (depth 1 in) to the centre of the rod pivot hole and this lever has a slight bend in the longer section..To suit the CW front forks, the front lever has a much more pronounced bend ( as in your pics) and is only 2 7/16 in ( or so) to obtain a straight line from the brake adjuster point on the LHS fork..The central pivot hole is again ½ in dia but only  about 5/16 in deep.
The TS model had a quite different design of rear lever and was quite long although I have seen a similar but shorter type with
a ⅜ in central pivot hole and 3 ¼ in dimension...For interest, a  TS I once owned had a really effective and non-grabbing rear brake but the  brake material had been hand carved from wood ( type unknown)..