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Started by Rex, 20 Aug 2017 at 12:01

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Rex

Hi all, new member and latest owner of a 1951 Douglas Mk 5. Need a bit of tidying but apparently nothing too onerous.
First job is to rebuild the wheels, a job I always do myself and enjoy, but on this bike the parts book shows four different length spokes on the front wheel, and three on the back wheel.
A steel rule shows that the "one side pairs" inner and outer are maybe 1-2mm different in length, which would be within the general tolerances of old spokes in an old wheel anyway.
So, do I supply CWC with seven different patterns for front and back  (as per the original Douglas parts book) or the more usual four (as they're so close in length that the difference would be immaterial?)
Thanks!

Rex

After further research I'll answer my own question.
It appears that the big differences are the spoke heads' angles...80' 90' and 100' so it looks like a tricky logistics exercise is in order!

Andy Smith

Hi Rex
I suppose it depends on how "enthusiastic" you are, I dont think that Douglas or British industry generally had really embraced the concept of parts interchangeability or commanality (another nail in the coffin perhaps) so carried on with pre-war practices. As you say building wheels is somthing you enjoy so presumably you are practiced and in the best position to judge, Personally without having measurements to hand I would order four sizes but if you enjoy a challenge and it won't cost more get seven but get on so you can enjoy riding it before the season ends Best wishes Andy

Rex

Hi Andy, if in doubt, read and follow the manual!
Bit of a faff compared to the usual two spoke-lengths per wheel, but best do it as per the book, and as you say, I might get a ride in before the Autumn.
Cheers.

Andy Smith

I don't think spokes are available in different head angles or at least I have never seen rebuilt wheels with the correct ones some are shocking, Sorry can't find a tongue in cheek emoji. Andy

cardan

Hi Rex,
If you'd like to do it "by the book", you can buy straight spokes (0 degree bend) and set them yourself. If they are "normal" spokes (it might be different for stainless) you get one "set" for free - no need for heat treating or anything.
For the task I built myself a little jig based on an old hinge, mounted in the vise. With a bit of ingenuity you can get the elbow length and angle you desire, even beyond 90 degrees.
I'm not sure about stainless, except to say it's a bad idea to try to change the angle after they are made. If you want to try, maybe heat them to dull red, set them, and leave them to cool very slowly in a container of lime. Best to check with an expert!
Have fun,
Leon

Rex

 {Answering Andy} In my opening post I was thinking just  that, and  if I just sent the wheels to {fill in one of the national wheel builders) they most likely would have set the head angles to the median 90' and used that for all seven varieties of spoke.
Would've likely made no difference, other than not being "right".