New Departure Model D Dating

[scrubbinrims]

Probably most of you have noticed the both the brake arm and perhaps the cog securing nut are different is the span of New Departure Model D production and since there is a lack of date coding, I thought it would be a good idea to document some of these details and enlist your assistance in placing their context.
This could help folks date their bicycles +/- a year if there is a logical progression to it.

I am not sure of the exact year the Model D first appeared (following the Model C), but I do not believe it was before the balloon period of 1933 or it was about that time.

There are 4 different styles of brake arms and I list them in order of appearance...

-Little arm "New Departure=Model D"

-Little arm "New Departure=Brake"

-Big arm (1940-41) "New Departure = Brake" I also believe during this transition, some were cad/zonc plated versus the earlier chrome)

-Big arm (postwar only, all cad/zinc plated) "NEW DEPARTURE"

 

[fordmike65]

Thanks for posting all these side by side for comparison. Will definately help get the right arm on the right bike. Noticed the first one posted has the Alemite fitting.

 

[scrubbinrims]

The cog nuts had more variety and I don't have a clear break point on these, but the earliest were smooth.
-First generation (I think) was a 3-indent

-Second generation had a 2-indent

-I do not believe there was a 1-indent smooth cog nut

 

[rustjunkie]

The 40-49 was also in black.


Here's one I was wondering about the other day:

 

[scrubbinrims]

The second cog nut iteration was the textured style (I think).
It had either a 1-indent or 2-indent and possibly coexisted together, but not sure why.

- 1-indent (forgot to snap a pic, but it exists).

- 2-indent

 

[scrubbinrims]

The third iteration was also textured, but had a valley.
These were late prewar and had a 1-indent or a 2-indent.
At least in my stash, the 1-indent had "New Departure" stamped in the nut consistently.

- 1-indent

- 2-indent

 

[scrubbinrims]

The 4th cog nut style was the one that Scott posted which has 3-indents, is stamped "New Departure," smooth and a layered appearance.
I believe this is postwar, but I am not sure since I don't have many postwar bikes to reference.

 

[scrubbinrims]

Besides the typical oil port with hinged cover, I have noted a new departure Model D without any oil port at all and they also did not have writing, so my thought are that they are the very earliest.
Also, for Elgins from roughly 1936-1938 an alemite port was used in place of the typical port and I am not aware of any other manufacturer advertising or using this alemite specialized fitting on their hubs.

 

[scrubbinrims]

So that's what I have to post.
If you have an original bike with its original New Departure Model D wheels and certain of its year, please feel free to add what brake arm is present and what cog nut is used.
Thanks, Chris

 

[rustjunkie]

A little more info:
The little brake arm hubs use a different disc support sleeve.
The knurled & grooved sprocket set nut was used pre- and well into post-war: part of the Delta stoplight switch rides in the groove.
DD sprocket set nut is different than D: the center hole is ~2mm smaller.