Reynolds 

A friend of mine bought this frame a few days ago. It's a Dazzan, made in Italy probably in the '90s for Octavio Dazzan, an Argentinian racer and bike shop owner. The used frame was in the shop backroom, my friend bought it and built it with some Campagnolo parts he had lying around in his own shop (he's an avid cyclist and vintage bike collector). The frame has some interesting features, especially the octagonal main tubes, chainstays (not seatstays) and fork blades. Dropouts are Campagnolo, seatpost is 27.2. The paint is also not common, with some panels resembling marble. A decal says it was painted by Carlo Dossena, a famed bike painter who's still in business. The head tube decal says "Settimo Tse. To Italy".
My friend is very interested about this frame's background. I wasn't able to find information about it elsewhere on the web, so I thought probably someone in this great C&V forum knows about it:

cyclotoine

Be still, my beating heart.

Reynolds 

Some more pics:

Bianchigirll 

I want one.

Lazyass

This fluted Dacccordi has been on CL for awhile.

wrote4luck

I had one of those formed Daccordi turbo frames, they are just cold formed SL tubes. I think this bike is the same. Still, they are very high on the cool scale. The Daccordis even predate Colnago in formed tubes.

ETA that bb shell is the coolest I have ever seen.

Wileyone 

The Daccordi frames are completely different from the op's Dazzan...

I like the fact that the top of the Dazzan's BB is square. Rather cool looking.

CliffordK

Nice bike. It looks a little like my Colnago Spiral Conic, but that is a pure octagon, and very nicely finished.

Does your friend have one of these? I'm not sure what "size 6" means.

Vintage SMS Santini Dazzan Cycling Jacket Cycliste sz- 6 | eBay

wrote4luck

I would disagree. They both use formed SL tubes and custom cast lugs. I would bet good money these 2 frame builders got their tubes from the same source in Italy, albeit about 3 years apart. Builders could special order this stuff but it was not cheap. Seat tube/top tube lug is unique to both frames.

zze86

No clue on the bike, but that is some hotness right there. The paint job is really insane and I love how the BB lines up perfectly with the tubes, crazy attention to detail.

Is that a dent on the seat post or is it supposed to be like that? If so to what end? Either way, sizzlin.

Lascauxcaveman 

As far as gimmicks go, that's a pretty darn cool one Lovely bicycle!

Octagonal tubing, because the O.O.'s name is Octavio, duh.

CliffordK

In the 80's and 90's, Campy introduced an Aero seatpost.

VeloBase.com - Component: Campagnolo C-Record (Aero type, 180mm)
VeloBase.com - Component: Campagnolo Chorus Aero



It undoubtedly made the bikes faster

Wileyone 

Yes I would agree with you there. If they are SL they both probably got their tube sets from Columbus...

Gary Fountain

Wow - beautiful bike.

There are similarities with Rossin Prestige frames but these frames have 6 facets. The Rossin frames are made from Tange Prestige tubes.

zze86

Very cool! Must be like how painting anything red makes it 10x faster.

T-Mar

Therer's nothing new about frames with polygonal tubes. Caminade of France used octagonal tubing in the late 1930s and they were even more unusual in that they were aluminum and riveted! . Monark of the USA had hexagonal aluminum tubes around the same period. In the late 1960s and early 1970s, Sanki of Japan sold entry level lighweights with hexagonal steel tubing under the Jupiter and University brands.

T-Mar

Based on my research Gilco appears to have been a subsidiary of A.L. Colombo (Columbus). It was established in 1946 by Colombo's son Gilberto to design and manufacture sports cars. Gilco produced tubing designs for Columbus but also hired out to produce proprietary designs for other manufacturers. Columbus' MS (Multi-Shape) tubing is a Gilco design and the tubing decals bear the Gilco's "G" logo and states "Gilco Design". Unfortunately, Gilco has become a generic term to refer to any non-round, cold formed, tubing shapes, much the same as Kleenex and Ski-Doo are used to refer to any facial tissue or snowmobile, even though they are brand names.

Reynolds 

Thanks all! I knew about the Gilco in Colnagos and the Caminargent - in fact my friend has one in his collection. New to me are the Daccordi and Rossin shaped tubes. The Daccordi seat lug looks similar to the Dazzan.
Was there any advantage with polygonal tubes or was it just to be different?

T-Mar

Altering the shape of the tube affects it rigidity. A round tube is equally rigid in all directions (assuming uniform thickness). Ideally, you want a bicycle to be stiffer laterally than vertically, as the lateral stiffness preserves the handling and transfers more power, while decreased vertical stiffness absorbs more road shock and provides a more comfortable ride. Altering the shape allows the designer to selectively increase the stiffness in specific directions, without the need to resort to increased tube thickness, which would increase weight.

Most members are aware that a larger diameter tube is stiffer than a smaller diameter tube. As the diameter increases, so does the stiffness. When you take a round tube and deform it into an oval, it is has a minor and major axis. The major axis is longer than the diameter of the previously round tube and it will be stiffer than the previous round tube, in that direction. The minor axis will be shorter than the old diameter and the oval tube will be less stiff than the round tube in that direction.

Oval tubes, as used on time trial and triathlon bicycles are more stiff vertically than laterally. This is the reverse the ideal situation, but in this case we are looking to make the tubes narrower for the purpose of reduced aerodynamic drag and the relatively steady power output of this type of event will not have as much effect of the lateral rigidity.

In the very late 1980s it became popular to ovalize the bottom bracket ends of the seat and down tubes on ATBs. The major axes were oriented laterally to increase lateral stiffness of the bottom bracket. It was even seen on some road frames, such as the Bianchi Superest II models.

When tubes are polygonal, they will still have a major and minor axes. Basically, they will be stiffer in the directions across the apexes and less stiff in the direction across the flats. Assuming that they were all cold formed from a tube of the same diameter, for any regular polygon (i.e. equal length sides and angles) the differential between the major and minor axes will become less as the number of sides increase. Basically, a octagon would would be less stiff than a hexagon across it apexes but stiffer across the flats, assuming they were both formed from a tube of the same diameter and thickness.

A longitudinal indentation along a tube works like a u-shaped stiffening channel applied to piece of sheet metal, such as a car hood. Indentations along the side of a tube will increase lateral stiffness.

By altering and orientating the shape of a tube, a designer can tailor the stiffness of a frame to more closely approach his vision of an ideal frame. Basically, it increases the flexibility of steel tube design and when used in conjunction with tubes of varying wall thickness and diameter, approaches the design flexibility of carbon fibre monocoques.

Reynolds 

Thanks T-Mar, great explanation. My '92 KHS has round tubes ovalized at the BB like you say.