The cost for material is not enough to make up for the many more steps to butt the tube. Seamless tubing is more expensive because it takes many more steps to make compared to seamed. True Temper is seamed, but the weld is done nicely and then drawn over a mandrel. This makes the bore smooth, you cannot see the weld normally. The properties are very similar to seamless. I believe the FAA requires airframe CrMo tubing to be seamless. In all my framebuilding experience I only had one frame fail beacause of defective tubing. A lap seam in a 531 down tube. They gave me a new tube! Normally I would inspect each tube before the frame was made, sometimes you could see lap seams.
Jim Merz Big Sur Ca
On Fri, Jun 25, 2010 at 8:27 AM, Don Wilson <dcwilson3@yahoo.com> wrote:
> Thank you, Norris, for your recollection of CAMUS tubing.
>
> As usual, your wealth of knowledge triggers another question.
>
> Did Reynolds innovation of double-butted tubing reduce the quantity of
> steel used in each tube, and so lessen the raw material cost/unit (and per
> unit shipping cost on both receiving steel and shipping tubes) of each tube?
>
> At their volumes, and economies of scale, even slight reductions in steel
> required per tube could yield significant cost savings, especially if the
> additional technology costs of double butting could be rather quickly
> recovered.
>
> I know they charged more for DB tubes, but that would just have been all
> the sweeter for Reynolds. Firms sometimes charge more, at least early on,
> for "advances" (especially patented ones) that have been undertaken, largely
> because they saved cost. Just curious if that were the case with Reynolds DB
> tubing.
>
> Thanks in advance.
>
>
> Don Wilson
> Bandon, OR/Los Olivos CA USA
>
>
> --- On Fri, 6/25/10, Norris Lockley <nlockley73@gmail.com> wrote:
>
> > From: Norris Lockley <nlockley73@gmail.com>
> > Subject: [CR] It Seams so unbelievable
> > To: classicrendezvous@bikelist.org
> > Date: Friday, June 25, 2010, 4:07 AM
> > It appears that my little anecdote
> > about Mercier's decision to drop Reynolds
> > 531 tubing due in part to problems of splitting, as
> > recounted to me by M
> > Rigobert, lightweight cycles specialist of Annecy,
> > has stirred up a bit of
> > a hornet's nest.
> >
> > Since posting it I have had a look through my 'Black
> > Museum' - the sort of
> > scrap corner where many framebuilders accumulate various
> > horrors of
> > frame-building. The Raleigh seamed head-tube is still in
> > the bin alongside
> > another crunched Raleigh 531DB touring frame whose tubes
> > also show some
> > evidence of being seamed.
> >
> > Reynolds 531 is of course the name of a certain
> > manganese-moly alloyed steel
> > that was made into tubes. As most cyclists know the tube,
> > it is usually but
> > certainly not always DB - double-butted, a special process
> > invented by
> > Rynolds to make lighter tubes that retained many of their
> > original physical
> > properties. Additionalaly I think that we, particularly
> > frame-builders, have
> > assumed it is always solid-drawn ie seamless not seamed and
> > simillarly we
> > have assumed that a solid-drawn tube is far better and
> > reliable than a
> > seamed one - not without good reason.
> >
> > In the early 80s I met up with a Parisien frame-builder ,
> > AMR, who
> > introduced me to a French brand of tubes called CAMUS. This
> > firm produced
> > the first full set of tubes designed specifically for
> > low-profile frames, in
> > that the top-tube was banana-shaped, and the seat-tube had
> > the double
> > compound curve, fork blades and stays being all
> > aero-profile, on the
> > European market.
> >
> > The tubes were excellently presented, very light..and had
> > excellent working
> > properties but turned out to be seamed ones not seamless
> > and not DB. I used
> > dozens of these aero curved-tube sets..and many other
> > standard tubing sets
> > made by CAMUS...and never had a single problem...not a
> > single split or
> > crack. Some riders preferred the tubes to the extralight
> > sets produced by
> > Columbus.
> >
> > Examining the interior walls of the tubes would yield no
> > indication that the
> > tubes were seamed - there being neither a ridge nor a
> > discoloured line to
> > indicate the butt-weld. Perhaps the most surprising
> > aspect of the tubes is
> > that the PG seat tube that had a wall thickness of 0.8mm
> > could be bent in
> > the compound curve without any distortion or 'crinkling' of
> > the tube..
> >
> > Unfortunately CAMUS tubing was never a strong enough
> > company to survive the
> > cycle industry's move into aluminium. The various series
> > were extremely
> > versatile and very widely used by the artisan builders of
> > central and
> > northern France.
> >
> > Norris Lockley
> >
> > Settle UK