Making a bespoke Llewellyn

Dazza · 14 Luglio 2011

geminiani ha scritto:
Ciao Dazza, posso chiederti un favore??? Riusciresti a fare un piccolo video in cui "si vede" l'ottone scorrere tra la congiunzione e il tubo?
Doriano mi raccontava che "l'ottone si vede scorrere e riempire ogni spazio" ma è una cosa che non ho molto capito. Grazie. ;o)

I will try to explain
when brazing a lug and tubes
one gets the temperature of the tubes and lug even and to the correct heat for the braze to flow from one end of the lug to the other end of the lug.
The operator can witness this "flow" from one end to the other.
With brass brazing (used in production because it is cheaper) the operator of the torch (flame) judges the correct temperature by the colour of the steel, it will be a very bright orange colour.
With Silver brazing which used much lower temperature you judge the correct moment to start and draw the low of braze through the lug by the colour and appearance of the flux. Silver generally is better for the metal and has much less distortion to the tubes so I like to use it. The sliver braze is 56% real silver so it is very expensive.
The skill is making a distortion free joint, with clean shorelines and no spills over the lug and tubes to clean up.
A joint that is washed free of flux and is not yet filed or sanded is the confirmation of skilled brazing.
A perfect brazed joint is impossible, but it is the goal every time I turn on the torch to braze. I like to show real pictures of the joints I have brazed, to show what really happens. Not the marketing selected pictures for websites and brochures.

sdg71 · 14 Luglio 2011

Dazza ha scritto:
a Custodian
and a Crescendo bikes leave this week

Hi Dazza!!

Your bikes are simply wonderful......in my new frame (Luigino...guess who's the builder....) i've also a custom stem with your lugs....so there's a little part of your wonderful work in my bike....i hope this collaboration with the "grey big man from Caldonazzo" will never end!

Thanks again for sharing with us the excellent result of your work!

Dazza · 14 Luglio 2011

sdg71 ha scritto:
Hi Dazza!!

Your bikes are simply wonderful......in my new frame (Luigino...guess who's the builder....) i've also a custom stem with your lugs....so there's a little part of your wonderful work in my bike....i hope this collaboration with the "grey big man from Caldonazzo" will never end!

Thanks again for sharing with us the excellent result of your work!

Thank you very much for your nice compliments, they are much appreciated.
It has been a pleasure to know the "grey big man from Caldonazzo" and I look forward to many years of enjoyment and interaction with him.
Thank you
Cheers Dazza

Dazza · 14 Luglio 2011

this time a Custodian in the signature finish and it will be painted Cosgrove Candy Apple Sun.
The frame design is directed to comfortable riding bicycle.

the hairy arm attacks the shoreline of the front dropout to give a concave shore line shape that I think is a lot sexier :) than my hairy arm :wacko:

geminiani · 15 Luglio 2011

Dazza ha scritto:
I will try to explain
when brazing a lug and tubes
one gets the temperature of the tubes and lug even and to the correct heat for the braze to flow from one end of the lug to the other end of the lug.
The operator can witness this "flow" from one end to the other.
With brass brazing (used in production because it is cheaper) the operator of the torch (flame) judges the correct temperature by the colour of the steel, it will be a very bright orange colour.
With Silver brazing which used much lower temperature you judge the correct moment to start and draw the low of braze through the lug by the colour and appearance of the flux. Silver generally is better for the metal and has much less distortion to the tubes so I like to use it. The sliver braze is 56% real silver so it is very expensive.
The skill is making a distortion free joint, with clean shorelines and no spills over the lug and tubes to clean up.
A joint that is washed free of flux and is not yet filed or sanded is the confirmation of skilled brazing.
A perfect brazed joint is impossible, but it is the goal every time I turn on the torch to braze. I like to show real pictures of the joints I have brazed, to show what really happens. Not the marketing selected pictures for websites and brochures.

Grazie Dazza! Ho capito la tua spiegazione anche se non condivido la frase (used in production because it is cheaper) direi che nella sostanza dovrei aver compreso. Mi piace l'entusiasmo che hai nella ricerca continua di una perfect brazed. o-o

Ho notato che nei disegni che pubblichi non indichi rake e angolo sterzo (non lo fa nessuno dei miei telaisti preferiti, buon segno!). Volevo però chiederti come sei riuscito a determinare le tue geometrie, usi le stesse di Hoffy Cycles? Hai sviluppato delle tue geometrie? E per questo hai avuto dei tester o ti fidi solo di te stesso come tester?
Esiste "un modo standard" per testare la guidabilità di un telaio?

Dazza · 15 Luglio 2011

geminiani ha scritto:
Grazie Dazza! Ho capito la tua spiegazione anche se non condivido la frase (used in production because it is cheaper) direi che nella sostanza dovrei aver compreso. Mi piace l'entusiasmo che hai nella ricerca continua di una perfect brazed.

Ho notato che nei disegni che pubblichi non indichi rake e angolo sterzo (non lo fa nessuno dei miei telaisti preferiti, buon segno!). Volevo però chiederti come sei riuscito a determinare le tue geometrie, usi le stesse di Hoffy Cycles? Hai sviluppato delle tue geometrie? E per questo hai avuto dei tester o ti fidi solo di te stesso come tester?
Esiste "un modo standard" per testare la guidabilità di un telaio?

I brass brazed all my frames till ten years ago
but like many others I found silver brazing is much better now for maintaining alignments in the build process due to less distortion. It is true that today's modern steel tubing is much better for reduced loss of mechanical properties with the higher temperature of brass brazing, compared to the 531 and SL steels.
This was driven by TIG welding requirements. (which melts the parent tube material)
Silver is $20 a stick (56% silver)
Brass is 50 cents. (manganese bronze)

Geometry.
I do not follow what I knew at Hoffy cycles.
With any bike design the most important thing is to plot the position of the rider first (the contact points)
then the frame is drawn to fit under this to serve the true function of the bicycle. It is the same process for a track racing bike, road bike, randonneur or a touring bicycle.
How this is determined is huge subject.
Many myths and marketing spiels are thrown about.
Over the years I have arrived at my design criteria intepretation for each particular type of bike. This is a huge subject, it will never end.
There are no new discoveries to be found about bicycle geometry, for 100 years and after billions of bicycles the criteria has been thrashed out by many experiments and production.
but I will say that it is important for the designer to make the correct choices for each rider. That is the important skill, which may take many years of experience and direction to do well.
Make the correct bicycle design for the rider
not the current design that is selling well this year.

Any questions?

geminiani · 15 Luglio 2011

Dazza ha scritto:
I brass brazed all my frames till ten years ago
but like many others I found silver brazing is much better now for maintaining alignments in the build process due to less distortion. It is true that today's modern steel tubing is much better for reduced loss of mechanical properties with the higher temperature of brass brazing, compared to the 531 and SL steels.
This was driven by TIG welding requirements. (which melts the parent tube material)
Silver is $20 a stick (56% silver)
Brass is 50 cents. (manganese bronze)

Ecco, se mi parli di distorsioni non posso che essere daccordo con te. Quello che non mi tornava è che fosse solo una questione di prezzo quando ci sono telaisti che vendono i loro telai a più di 2000$ brasati con l'ottone.

Dazza ha scritto:
Any questions?

Scusami, stò un po' approfittando della tua disponibilità... :eek:

Dazza · 15 Luglio 2011

geminiani ha scritto:
Ecco, se mi parli di distorsioni non posso che essere daccordo con te. Quello che non mi tornava è che fosse solo una questione di prezzo quando ci sono telaisti che vendono i loro telai a più di 2000$ brasati con l'ottone.

Scusami, stò un po' approfittando della tua disponibilità... :eek:

Maybe I am losing the gist in the translation

Fact. Silver has much less distortion in brazing thin walled tubes
and most independent frame builders choice silver because it works better for them.
In the factory, you must make the frame for a whole sale price to sell to the retailer and the retailer must make a profit and taxes compound etc
so the manufacturing cost is very important.
Brass brazing will still make very nice frames
but silver is sweet!

also stainless steel parts and tubes must be brazed with Silver

Brass brazing with lugs has NO structural advantage s
over
Silver brazing
The shear strength of brass is better for cantilever bosses and can be argued much better for fillet brazing tubes without lugs.

Dazza · 15 Luglio 2011

silver brazing must be used to join the stainless steel dropouts to the Columbus Niobium tubes

then the filing
sanding with 80 grit
then sanding with 180 grit
then 240 grit
then 1000 grit under balsa wood sticks
it takes many hours to prepare the parts for polishing

and then the polish only takes 5 mins! (to be done later when the rear dropouts are ready

Dazza · 15 Luglio 2011

The M5 eylets are cut off the rear dropouts as this is race style bike
and the steerer tube is brazed into the fork crown and cleaned

Dazza · 16 Luglio 2011

Mary Ann in our lounge room doing pictures for the website :eek:

Dazza · 16 Luglio 2011

why does not every frame have one of these ‪Colombine Quick Chainger on a Llewellyn bike‬&rlm; - YouTube

‪Colombine Quick Chainger on a Llewellyn bike‬&rlm; - YouTube

sante pollastri · 16 Luglio 2011

Dazza ha scritto:
why does not every frame have one of these ‪Colombine Quick Chainger on a Llewellyn bike‬&rlm; - YouTube

‪Colombine Quick Chainger on a Llewellyn bike‬&rlm; - YouTube

è una tua invenzione?

Dazza · 16 Luglio 2011

sante pollastri ha scritto:
è una tua invenzione?

No it is from here
http://www.columbinecycle.com/bicycles.php
http://www.columbinecycle.com/other_products.php
the brothers John and Richard Murphy invention

I have used them on all my Llewellyn frames for over 15 years

sante pollastri · 16 Luglio 2011

Dazza ha scritto:
No it is from here
http://www.columbinecycle.com/bicycles.php
http://www.columbinecycle.com/other_products.php
the brothers John and Richard Murphy invention

I have used them on all my Llewellyn frames for over 15 years

è una buona idea,probabilmente quasi nessuno ne è a conoscenza.

gianluigi · 16 Luglio 2011

L'uovo di Colombo!
Semplice e geniale.

pcarp · 16 Luglio 2011

gianluigi ha scritto:
L'uovo di Colombo!
Semplice e geniale.

anche se con scopo differente lo trovo molto simile al famoso dente di cane.....

pcarp · 16 Luglio 2011

sante pollastri ha scritto:
è una buona idea,probabilmente quasi nessuno ne è a conoscenza.

visto pure il sito di Columbine......qualche congiunzione fa apparire l'arabesque, tuo sogno, decisamente sobrio :-)

sante pollastri · 16 Luglio 2011

pcarp ha scritto:
visto pure il sito di Columbine......qualche congiunzione fa apparire l'arabesque, tuo sogno, decisamente sobrio :-)

vero,nemmeno commento,ho aperto e chiuso il sito in una frazione di secondo...

Ciclo · 18 Luglio 2011

pcarp ha scritto:
anche se con scopo differente lo trovo molto simile al famoso dente di cane.....

Diciamo che il concetto è simile... Il dente di cane serve durante il movimento, questo da fermo.

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