Mr. Freeman/Davidson and anyone else with Prestige experience,
"I straightened and rode it a bit more, and it eventually the .7/.4 Prestige downtube cracked."
Over the years some builders have commented to me about those thin .7 .4 Prestige tubes you mentioned. Most agree they have a super compliant and "springy" ride, but the question that always gets different answers is, how durable is this Prestige tubing over the long haul? Some say they never had a problem with it, I know for instance that John Murphy is a huge fan, others say its prone to cracking more eaily than other types. Any thoughts/experiences on this? Thank You Jeremy Lieberman New York City, NY USA
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> CR
>
> Today's Topics:
>
> 1. Re: Ed Litton's cambio corsa bike (Joe Starck)
> 2. Re: More about Silver vs Brass
> 3. Saddle disassembly & riveting redux (Amir Avitzur)
> 4. "Blue Bianchi" (Jack Gabus)
> 5. Re: More about Silver vs Brass (Kurt Sperry)
>
>
> ----------------------------------------------------------------------
>
> Date: Tue, 27 Sep 2005 11:28:51 -0700 (PDT)
> From: Joe Starck <josephbstarck@yahoo.com>
> To: classicrendezvous@bikelist.org
> Cc: themaaslands@comcast.net
> Subject: Re: [CR]Ed Litton's cambio corsa bike
> Message-ID: <20050927182851.14131.qmail@web34305.mail.mud.yahoo.com>
> In-Reply-To:
<092720051754.26413.43398759000929500000672D22007637049C0B020E049C0E0E030A08
9B@comcast.net>
> Content-Type: text/plain; charset=iso-8859-1
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Precedence: list
> Message: 1
>
> --- themaaslands@comcast.net wrote:
>
> > It should perhaps be pointed out that Ed's bike is a
> > cambio corsa bike and not a Paris-Roubaix model.
> >
> > I can give you a bit of history regarding this
> > particular frame. The lugs, drop-outs and such came
> > from what I believe was an early 1950's Aquila
> > frame. I had bought the frame sight unseen in Italy
> > and it turned out to be totally shot, so bad in fact
> > that a repair was not viable. Ed decontructed the
> > frame and retrieved the lugs, drop-outs and fork
> > crown. He then used the cambio corsa dropout jigs
> > that Roland Della Santa has and built himself the
> > frame. This worked out very well as Ed is definitely
> > taller than your average Italian from the 50's and
> > would have had great difficulty to find himself a
> > large enough frame otherwise. Ed still has a few
> > more cambio corsa dropout frames in his workshop, so
> > if you want a made to measure Ed Litton cambio corsa
> > bike, it is possible.
>
> Steven,
> Another listee posted some links to this bike, I
> think, but they didn't work for me. Can you or anybody
> post pics of the frame, build, jigging, and such? A
> few years back, Grant Petersen asked me about my
> interest in making one, I think he said he could get
> the parts and jigs, but I guess I said I wouldn't know
> what to charge as I wasn't familiar enough with the
> design.
> Joe Starck
> Madison, Wisconsin
>
>
>
> ------------------------------
>
> Date: Tue, 27 Sep 2005 14:31:07 EDT
> From: RDF1249@aol.com
> To: brianbaylis@juno.com
> Cc: classicrendezvous@bikelist.org
> Subject: Re: [CR]More about Silver vs Brass
> Message-ID: <213.a0df9d4.306ae9eb@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 2
>
>
>
>
> OK - I spoke with Bill Davidson about his recollections of this test and
as
> usual, he remembers a lot more detail than I do. I had most of it right
but
> I hate to say Brian is correct and I remembered wrong on one point. None
of
> the silver joints pulled away from the tubes in this particular test.
More
> about that in a second.
>
> The device we used was borrowed from Charlie Cunningham. Just as I said,
it
> held the front triangle rigidly while a lever was used much as a fork
would
> be in a front end crash, to wrinkle the front end, using a hydraulic jack
as
> the power. A strain gauge was hooked up to this to measure the force
> required, which would tell you how resistant the frame was against an
impact. The
> absolute amount of force required is irrelevant due to the leverage
involved,
> only the relative differences are significant. Here are the results that
> Bill remembers: With Silver, the frame wrinkled right near the points of
the
> lugs. With brass, it wrinkled about 1 cm down from the lugs. This
didn't
> change with the different tubing or lugs, just with silver vs brass.
This is as
> you might expect, since brass requires a higher temperature than silver
and
> so the heat affected zone is further out. Bill says this is significant
> because it means that the weakest point of the tube, the margin of the
> heat-affected zone, is right near those nasty stress risers - the points
of the lugs -
> in a silver brazed frame. In a lifetime of flex cycles, if it is going
to
> break from fatigue, that is where it will go first. We have seen a lot
of
> frames go like that. The brass-brazed frame which wrinkles farther
down, would
> at least be stronger or at least more uniform where the points are and
less
> likely to be taken out by fatigue cycles.
>
> Another significant thing Bill mentioned: Remember I told you about
brazing
> with a big rosebud torch to preheat the joints so you can do it faster?
We
> did some that way and some the usual way with only a small torch. Bill
said
> the preheated joints withstood a lot more force according to the strain
> gauge, although ultimately they failed in the same manner. That means
the frame
> should be able to survive a somewhat harder impact. Since we only braze
this
> way with brass (too much heat for silver) that is a point in brass's
favor.
>
> Now back to those silver joints coming apart. I didn't make this up. It
> just didn't happen during this test. We get a lot of crashed bikes in
for
> repairs, and Bill says he has seen many frames brazed with silver pull
apart
> during a crash. Not just ours, but from other very well known builders
too. I
> should point out that we have used Silver to braze also for many years on
very
> light tubing. I have seen a number of these too, and somehow remembered
them
> as being in the test. Some particular lugs are more prone to this than
> others. The Otsuya lugs that we used back the early 80s had very small
surface
> area behind the head tube, and these were more prone to coming apart, as
you
> might expect. I crashed my Davidson with these lugs in a high speed
front
> ender in 1988, and while it did wrinkle the frame pretty good, it didn't
come
> apart. Luck of the draw I think. I straightened and rode it a bit
more, and
> it eventually the .7/.4 Prestige downtube cracked so I rebuilt it. Bill
has
> seen a number of times where when the joint pulled apart, it left a thin
> layer of steel on the brazing material. He suggests that this has
something to
> do with how the metal cooled in the investment casting process, leaving a
weak
> surface layer. He started shining up the inside of lugs when he noticed
> this to remove that shear layer.
>
> Conclusions? Draw your own. It still seems to me that a frame can be
> stronger when brazed with brass and using a preheat torch in the hands of
a good
> brazer who can do it quickly, but there is nothing wrong with silver as
long
> as you don't plan to crash it. And if you crash, well, the frame is
probably
> the least of your worries.
>
> Ride safe
>
>
> Bob Freeman
> Elliott Bay Bicycles
> 2116 Western Ave
> Seattle, WA 98121
> 206-441-8144
> Home of Davidson Handbuilt Bicycles
>
>
> In a message dated 9/24/2005 11:31:13 P.M. Pacific Standard Time,
> brianbaylis@juno.com writes:
>
> I would have to see the testing device, the way you bulit the "test
> triangles", and a whole lot more before I would believe your story. No
properly
> brazed silver joint will fail before the tube in an impact. Seen lots of
them.
> Seen more broken joints (where tube did not break but braze joint did,
which is
> just as wrong with brass as with silver) on brass brazed frames than with
> silver by quite a large margin. I've seen a good number of relavatively
poorly
> brazed silver joints not fail after impact. It sounds to me like you
tested a
> bunch of improperly brazed silver joints. Probably better to use brass in
> that situation, but properly silver brazed joints have at least equal
strength
> to those of brass.
>
> For those of you out there who do not or have not built a good number of
> frames; there is no way to really decide which information is closeset to
the
> truth. Since I happen to know what I've seen and experienced, I know for
sure I
> don't buy this particular story.
>
> It is obvious that good bikes and excellent bikes can be made useing
either
> method and that the primary factor in that is the ability of the builder
and
> their intentions towards producing a quality product. But there is such a
> thing as reality. 700 frames a year is not the place for silver. Silver
is for
> those individually producing handmade frames with traits and features
that
> aren't part of low production work. It's a different world, different
> circumstances. Like I said, good that you did some testing and concluded
that for your
> circumstances brass worked better for you. Silver works better for the
type
> of work I do.
>
> Brian Baylis
> La Mesa, CA
> Show me, talk is cheap.
>
> -- RDF1249@aol.com wrote:
> I came into this thread late but I thought I would share a couple of
> tidbits.
> In the mid-80s, when we (Davidson Cycles) were building around 700 frames
> per
> year, we wanted some idea of what was going to happen to them in a crash,
so
> borrowed a destructive testing device (I forget who had it. Bicycling
Mag,
> maybe?) that simulated a front end crash. Made a bunch of front ends to
> test in
> it, with all different materials and methods but otherwise the same, and
> found, almost without exception, that the joint failed (came apart) when
> done with
> silver, and the tube failed behind the intact joint when brazed with
brass.
> What does that tell you? Well, given a hard enough impact you will
destroy
> a
> steel bike no matter, but the brass did make a stronger joint. Yes you
can
> braze at a lower temperature with silver, but if you are burning the snot
> out of
> it getting it to move around then you will do a lot more harm. I think
an
> experienced builder using brass will build a much superior bike to a
rookie
> with
> silver.
>
> It is not only the absolute temperature that is reached that degrades the
> steel, it is the length of time at that temperature. The longer it stays
> hot,
> the farther away from the joint the heat affected zone travels. It is
that
> margin of the heat affected zone that is where a frame will usually fail
in
> a
> crash. Keeping it closer to the lug, in the butted section, makes it
more
> likely
> to withstand a crash. So brazing it quickly is the answer to making the
> strongest frame. We developed a way to braze them very quickly. We
don't
> do a lot
> of lugged steel frames any more so I don't mine sharing the tricks. We
made
> little rings of brass that were the shape of the inside of the joint, and
> assembled the frame with them in there. The joint is heated quickly and
> evenly
> with a large, broad flame until red hot. You can see the brass ring in
> there as
> a shadow. Once it is gone you know the brass has melted, we switch to a
> small
> torch and work the heat around until brass comes out all the edges
evenly,
> and voila, you are done. Almost no cleanup involved afterwards. A few
of
> our
> brazers would use the big torch in one hand and the small torch in the
> other.
> We had fork crowns made with a shelf that the steerer butted against, and
> stamped out washers of brass that fit right in there and did the same
thing
> for
> the crown to steerer braze, and had rings inside the blade sockets too.
Two
> guys could braze up 30 steerer, crown, blade assemblies an hour that way.
> Again
> with almost no cleanup. And it leaves a little fillet of brass on the
> inside
> of the joint too to further strengthen it. You would never get
penetration
> that good by brazing from the outside only, and not nearly as fast.
>
> Another tidbit, and all framebuilders know this, but 853 Reynolds is
always
> brazed with brass. It doesn't get hot enough for the air-hardening to
> happen
> with silver.
>
>
>
>
>
>
>
>
>
> ------------------------------
>
> Date: Tue, 27 Sep 2005 20:36:06 +0200
> From: Amir Avitzur <avitzur@013.net>
> To: Classicrendezvous <classicrendezvous@bikelist.org>
> Subject: [CR]Saddle disassembly & riveting redux
> Message-ID: <JJEEKLDDELHGFDGDBELBEENLCFAA.avitzur@013.net.il>
> Content-Type: text/plain; charset=windows-1255
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 3
>
>
> By an odd fluke, my local hardware store had a box of brass rivets,
> forgotten by the original customer.
> The rivets have a 12 mm flat head and a 4 mm diameter shaft that is 9 mm
> long.
> The shafts are solid to the middle and then hollow.
>
> As some of the respondents to my inquiry noted:
> the shaft of the rivets do all the "work",
> the heads, besides holding the rivet in place, are mostly ornamental
> that is why the root of the shaft is solid
>
> Anyway, once I got them home I had to try replacing a rivet.
> So I drilled out an old one and placed new one in its hole.
>
> Rivet replacement is not difficult.
> It can even be done without a rivet setter as follows:
>
> cut the hollow shaft radially so that it will bend over easily
> hammer a cone (I used a punch) into the opening to bend the "petals"
> evenly
> use a ball peen hammer to finish the bend and tighten the rivet
> use a ball peen hammer to contour the head over the leather
> at all times support the other side of the rivet with a block of
> hardwood or piece of metal
>
> This takes time and patience, but can look quite nice afterwards.
>
> The technique gets a lot more complicated when the leather on the saddle
has
> been completely removed.
> I'll report on that when I get to it.
>
> Amir Avitzur
> Ramat-Gan, Israel
>
>
>
>
> ------------------------------
>
> Date: Tue, 27 Sep 2005 11:47:52 -0700
> From: "Jack Gabus" <jack@shermangabus.com>
> To: <classicrendezvous@bikelist.org>
> Subject: [CR]"Blue Bianchi"
> Message-ID: <MHELKCFNLJJCPOHKBLKAAEHGGFAA.jack@shermangabus.com>
> Content-Type: text/plain;charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 4
>
> Well it's back. This was from two or three week ago. The infamous "Blue
> Bianchi" Now he thinks it is a DeRosa. Ok everybody chime and let's
figure
> this one out. On list please.
>
> E-Bay # 7185236156
>
> Regards,
>
> Jack
>
> Jack (Giacomo) Gabus
> Laguna Beach, CA
> jack@shermangabus.com
> http://www.wooljersey.com/
>
>
> ------------------------------
>
> Date: Tue, 27 Sep 2005 11:59:34 -0700
> From: Kurt Sperry <haxixe@gmail.com>
> Cc: classicrendezvous@bikelist.org
> Subject: Re: [CR]More about Silver vs Brass
> Message-ID: <75d04b480509271159787870d2@mail.gmail.com>
> In-Reply-To: <213.a0df9d4.306ae9eb@aol.com>
> References: <213.a0df9d4.306ae9eb@aol.com>
> Content-Type: text/plain; charset=ISO-8859-1
> MIME-Version: 1.0
> Precedence: list
> Reply-To: kurt@fineartscrimshaw.com
> Message: 5
>
> Wonderful stuff there Bob, thanks. While the methodologies might be
quibble
> d
> with, the results are still highly instructive.
> There's a TON of mythology related to our beloved lightweight bikes, some
> myths will withstand empirical testing; some won't.
> Kurt Sperry
> Bellingham WA
>
>
> >
> >
> > OK - I spoke with Bill Davidson about his recollections of this test and
> > as
> > usual, he remembers a lot more detail than I do. I had most of it right
> > but
> > I hate to say Brian is correct and I remembered wrong on one point. None
> > of
> > the silver joints pulled away from the tubes in this particular test.
Mor
> e
> > about that in a second.
> >
> > The device we used was borrowed from Charlie Cunningham. Just as I said,
> > it
> > held the front triangle rigidly while a lever was used much as a fork
> > would
> > be in a front end crash, to wrinkle the front end, using a hydraulic
jack
> > as
> > the power. A strain gauge was hooked up to this to measure the force
> > required, which would tell you how resistant the frame was against an
> > impact. The
> > absolute amount of force required is irrelevant due to the leverage
> > involved,
> > only the relative differences are significant. Here are the results that
> > Bill remembers: With Silver, the frame wrinkled right near the points of
> > the
> > lugs. With brass, it wrinkled about 1 cm down from the lugs. This didn't
> > change with the different tubing or lugs, just with silver vs brass.
This
> > is as
> > you might expect, since brass requires a higher temperature than silver
> > and
> > so the heat affected zone is further out. Bill says this is significant
> > because it means that the weakest point of the tube, the margin of the
> > heat-affected zone, is right near those nasty stress risers - the points
> > of the lugs -
> > in a silver brazed frame. In a lifetime of flex cycles, if it is going
to
> > break from fatigue, that is where it will go first. We have seen a lot
of
> > frames go like that. The brass-brazed frame which wrinkles farther down,
> > would
> > at least be stronger or at least more uniform where the points are and
> > less
> > likely to be taken out by fatigue cycles.
> >
> > Another significant thing Bill mentioned: Remember I told you about
> > brazing
> > with a big rosebud torch to preheat the joints so you can do it faster?
W
> e
> > did some that way and some the usual way with only a small torch. Bill
> > said
> > the preheated joints withstood a lot more force according to the strain
> > gauge, although ultimately they failed in the same manner. That means
the
> > frame
> > should be able to survive a somewhat harder impact. Since we only braze
> > this
> > way with brass (too much heat for silver) that is a point in brass's
> > favor.
> >
> > Now back to those silver joints coming apart. I didn't make this up. It
> > just didn't happen during this test. We get a lot of crashed bikes in
for
> > repairs, and Bill says he has seen many frames brazed with silver pull
> > apart
> > during a crash. Not just ours, but from other very well known builders
> > too. I
> > should point out that we have used Silver to braze also for many years
on
> > very
> > light tubing. I have seen a number of these too, and somehow remembered
> > them
> > as being in the test. Some particular lugs are more prone to this than
> > others. The Otsuya lugs that we used back the early 80s had very small
> > surface
> > area behind the head tube, and these were more prone to coming apart, as
> > you
> > might expect. I crashed my Davidson with these lugs in a high speed
front
> > ender in 1988, and while it did wrinkle the frame pretty good, it didn't
> > come
> > apart. Luck of the draw I think. I straightened and rode it a bit more,
> > and
> > it eventually the .7/.4 Prestige downtube cracked so I rebuilt it. Bill
> > has
> > seen a number of times where when the joint pulled apart, it left a thin
> > layer of steel on the brazing material. He suggests that this has
> > something to
> > do with how the metal cooled in the investment casting process, leaving
a
> > weak
> > surface layer. He started shining up the inside of lugs when he noticed
> > this to remove that shear layer.
> >
> > Conclusions? Draw your own. It still seems to me that a frame can be
> > stronger when brazed with brass and using a preheat torch in the hands
of
> > a good
> > brazer who can do it quickly, but there is nothing wrong with silver as
> > long
> > as you don't plan to crash it. And if you crash, well, the frame is
> > probably
> > the least of your worries.
> >
> > Ride safe
> >
> >
> > Bob Freeman
> > Elliott Bay Bicycles
> > 2116 Western Ave
> > Seattle, WA 98121
> > 206-441-8144
> > Home of Davidson Handbuilt Bicycles
> >
> >
> > fineartscrimshaw.com http://fineartscrimshaw.com
>
>
> ------------------------------
>
> _______________________________________________
>
>
> End of Classicrendezvous Digest, Vol 33, Issue 105
> **************************************************