FRANK, I believe that B und O used the Be thin film to increase the cone stiffness without increasing the mass. Beryllium is used for orbital structures for it's stiffness. I used a scrap piece of tubing to make the tone arm. Be is a very dangerous material with which to work. The swarf can lead to berylosis, which is incurable. Jerry FRANK DERNIE wrote: > Hi Jerry, > I knew Be was outside the norm but did not realise it > was a factor of 6. Hans Metzger told be about trying > coated Be discs on the braking system of the sprint > version of the 917 - they never got them to work > though I don't know why. There are Be vapor deposited > domes on the speakers I use in my bedroom! > cheers > Frank > > --- Jerry Lehrer <jerryleh@xxxxxxxxxxx> wrote: > > > Frank, > > > > Most all structural metals have identical specific > > stiffness, EXCEPT > > Beryllium, whose specific stiffness is 6 times > > higher. Tubular beryllium > > > > replaced the aluminium tone arm shaft on my Linn > > Itok tone arm. > > > > Jerry > > > > Frank Dernie wrote: > > > > > I know nothing about bikes but I am very familiar > > with these > > > materials. Steel and Ally have more or less > > identical specific > > > stiffnesses so any difference will be due to the > > geometry - for > > > example the larger diameter tubes used in the ally > > frame for strength > > > will result in stiffer welded junctions. Carbon is > > nothing like either > > > steel or ally. The mechanical properties depend on > > the layup and > > > material choice, there is a huge variation in > > stiffness of different > > > fibres unlike metals where the strength can vary > > greatly between > > > alloys but the stiffness not much at all. The > > fibre orientation and > > > type of fibre will have a much bigger effect in > > carbon than metal > > > though the geometry of the joints will have the > > biggest influence on > > > stiffness. Carbon can have significant internal > > damping, depending on > > > resin system. Metals have negligible internal > > damping.A carbon frame > > > has more potential than a metal one, I would > > expect an optimised > > > carbon frame to cost between 10 and 100 times more > > than a metal one so > > > they probably either don't exist or the metal ones > > are much more > > > profitable :-)Frank On 8 Jun, 2006, at 02:18, > > Douglas Nygren wrote: > > > > > >> One further thought about bikes that pertains to > > cameras. > > >> > > >> > > >> > > >> > > >> New developments in bike design and construction > > have led to many > > >> carbon fiber (ie. plastic) and aluminum bikes. > > They have displaced > > >> the old standard whcih were made of metal, often > > called > > >> "Cro-malloy." > > >> > > >> > > >> > > >> The carbon and aluminum bikes are lighter. Some > > are more rigid than > > >> the steel. They climb well, but they don't > > descend as well. They hop > > >> with every bump. The steel absorbs this better. > > On a long ride, the > > >> aluminum beats the rider up. They are so stiff > > that the very quality > > >> that allows them to climb better--ie. the > > stiffness that transfer > > >> the energy better--also allows the energy from > > bumps to return > > >> upward and into the rider. On a long ride, this > > does a number on the > > >> rider. Steel treats the rider better. > > >> > > >> > > >> > > >> I think you'd be hard pressed to find a steel > > bike on the Tour de > > >> France these days. Carbon is in, and it's a lot > > like aluminum. > > >> > > >> > > >> > > >> I perfer steel, and I prefer film to digital. I'm > > afraid I'm > > >> becoming anachronistic. > > >> > > >> > > >> > > >> Doug > > > > > > > > > ---------------------------------------------------------------- > > > No virus found in this incoming message. > > > Checked by AVG Free Edition. > > > Version: 7.0.394 / Virus Database: 268.8.2/357 - > > Release Date: > > > 06/06/2006 > > > > > > > --- > Rollei List > > - Post to rollei_list@xxxxxxxxxxxxx > > - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' > in the subject field OR by logging into www.freelists.org > > - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with > 'unsubscribe' in the subject field OR by logging into www.freelists.org > > - Online, searchable archives are available at > //www.freelists.org/archives/rollei_list > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.0.394 / Virus Database: 268.8.2/357 - Release Date: 06/06/2006 --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list