[ARC5] Pantograph machine?

[J. Forster]

>> No. I think it's an engraving head. It is not a spinning router bit,
>> like a Green uses.
>>
>> The workpiece is below the stylus and you can see radial dial lines if
>> you look very closely.
>>
>> However, AFAIK, no ARC-5 sets used dials hogged out of a solid chunk of
>> aluminum. They are either bakelite or stamped aluminum.
>
> Is it possible she places a totally black ARC-5 dial onto the shiny round
> thingy, then the machine paints the dial divisions, together with their
> Kc/s numerals, eg. 3.5, 3.6, etc, as well as the central frequency range?

I don't think so. The piece under the stylus is partly engraved. None of
the others are.

>> It is possible she is making master molds for plastic dials, IMO.
>
> In 1942? I know plastics were around back then because the 1938 Ford V8
> I owned in the 1970's had original plastic window winder knobs, but one
> doesn't tend to find plastics used in 1940's military stuff.

Many of the ARC-5 dials are plastic. Later ones, I think.

My guess is they made a master, like she is making. Then the master is
heavily plated with a metal like copper, and used to mold the plastic
dial. Basically the same process as used to make 78 RPM records.

FWIW,

-John

======================
>
> 73 de Neil ZL1ANM
>
>
> On Wed, May 21, 2014 at 10:30 AM, J. Forster <jfor at quikus.com> wrote:
>
>> No. I think it's an engraving head. It is not a spinning router bit,
>> like
>> a Green uses.
>>
>> The workpiece is below the stylus and you can see radial dial lines if
>> you
>> look very closely.
>>
>> However, AFAIK, no ARC-5 sets used dials hogged out of a solid chunk of
>> aluminum. They are either bakelite or stamped aluminum.
>>
>> It is possible she is making master molds for plastic dials, IMO.
>>
>> FWIW,
>>
>> -John
>>
>> =================