Mark, Thank you for the explanation and detailed photos. It is very easy to see the difference now. I understand why master frame builders disliked them. It must take hours to get a proper finish. For mass produced factory bikes finish was not so critical, just the quickness of the build.
Jay Dubiel Halifax, VA USA
On 3/21/2010 10:54 PM, Mark Bulgier wrote:
> Jay Dubiel wrote:
>
>
>> I'm confused. The statement that Nervex are made by wrapping
>> sheet metal and welding seems odd for what I have in hand and
>> pictured. Beneath the chrome there is evidence of a course
>> surface, pitting and heavy grinding marks which I would think
>> might indicate a cast or forged piece. The inner tangs are
>> 4mm thick, how does that get wrapped?
>>
> I completely understand -- it does seem hard to imagine them wrapping
> such thick metal around, but they (Nervex/Dubois) were masters of it.
>
> I took some pictures of the raw crowns that make it clear that they are
> in fact hollow and made of sheet metal.
>
> The first pic is of the bottoms of the crowns, and shows off the Nervex
> hollowness well. The crown on the left is a Wagner, the other three
> Nervex. Look at the Nervex chevrons or "epaulets", clearly seen here on
> the _inside_ of the crown, showing that they are formed from sheet
> rather than machined in later, like Wagner chevrons.
> http://bulgier.net/
> (if the URL is too long and wraps, use http://tinyurl.com/
>
> This next photo shows the tops, showing what Chas. Colerich meant about
> the chevrons being pointed on the end with Wagner, but blunter or
> squared-off on the Nervex:
> http://bulgier.net/
> (or http://tinyurl.com/
>
> Two of the three Nervex crowns in my pictures have the feature cut that
> matches the classic Nervex Pro lugs. Feature cut on the third Nervex is
> plainer, looks better with Dubois or any regular non-curlicue lugs, and
> this is the cut on the orange fork in the photos Jay showed us earlier.
>
> Being hollow yet relatively large in their outside dimensions gives
> these crowns a very high strength-to-weight ratio. They are also
> relatively easy to heat up for brazing. I like 'em, but they were not
> popular with some framebuilders due to the relatively crude finish and
> the large amount of work required to make them look nice.
>
> Mark Bulgier
> Seattle WA USA