On 8/2/2020 8:07 PM, Frank Krygowski wrote:
On 8/2/2020 5:27 PM, Sepp Ruf wrote:
Frank Krygowski wrote:
On 8/2/2020 2:25 AM, Sepp Ruf wrote:
Frank Krygowski wrote:
On 8/1/2020 5:48 PM, Sepp Ruf wrote:
AMuzi wrote:

Neither a 1.0 metric nor a 26tpi gauge fits exactly
on those axles and
Sachs/SRAM doesn't state the thread. Even if you
decided that 'something
close' would do, there are no m11x1.0 nuts in common
use anywhere, not
autos, not McMaster-Carr or what have you.

From the SRAM techmanual gearhubsystems pdf (archive):
Axle - Ends Diameter - FG 10,5

(FG = Fahrradgewinde)

Your old Winkler-Rauch (book) has all the data on it:
Steigung 0,977; Flankenwinkel 60°;
Außendurchmesser 10,444; Flankendurchmesser 9,924;
Kerndurchmesser 9,404;
Gangzahl pro Zoll 26; Gewindetiefe 0,520;
Gewinderundung 0,163

I do think it's strange that they settled on
non-standard threading for
such a simple part. Despite claims, it can't be for
reasons of strength.

Just because Frank Krygowski (or some lean-brained,
Chicago corn trader MBA
bozo at SRAM, excuse my Polish), "thinks" a part is
non-standard does not
mean it really is not.

I've got no problem with non-standard _parts_. I do have
a problem with
non-standard _threads_. Threading standards have been
pretty stable for
many, many decades.

FG threads, whether they are copies of British threads or
not, were around
decades earlier than post-WW2 ISO.
[] any clue why they would have done that?

When they decided that the usual, thinner FG9,5 rear hub
axles weren't
strong enough for the growing O.L.D. of gear hubs,
somewhere past the 2sp
IGH era.

That was at least inaccurate. I just looked at a
technical drawing of a
1930's 2sp Torpedo hub with FG9,5 on the left, and FG10,5
on the right side
which includes the connection from the cable to the
internal shifting mechanism.

So was there a specific reason they couldn't go with 12mm
threads? (See
"Preferred Sizes" at
https://en.wikipedia.org/wiki/ISO_metric_screw_thread

Why would they? In the 1920's, did anyone engineer to
facilitate sourcing a
million nuts from the lowest Asian bidder?

Are you saying this SRAM hub was designed and built in the
1920s? If so, I won't complain about it's weird threading.



I understood Mr Ruf to mean that a Sachs 2 speed of that era
was engineered with RH 10.5x26 thread.

I assume someone at F&S reasoned that your basic 9.5mm
standard axle would be less strong with a hole in the
middle. Once that thread is supported with tooling the next
guy asks 'why not?'

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971