Fine Italian Steel
Mon, August 30, 2021 
On hearing the term “Fine Italian Steel,” one usually thinks of handcrafted steel frames, but in the early 1950s, Italy having made a quick recovery from the devastation of WWII, were producing some quite beautiful steel bicycle components.
There were no Campagnolo Groupos in the early 1950s, Campagnolo made quick release hubs and derailleur gears, and that was it. Pedals and cranksets were introduced in the late 50s.
The two main brands I remember were Gnutti and Magistroni, between them they made cranksets, bottom bracket bearings, hubs and headsets.
Gnutti made a really elegant cotterless crankset, (Pictured above.) that fitted onto a tapered and splined BB spindle, and was held in place with recessed Alen screws.
They also made a less expensive cottered crank, which was the one I used, pictured left.
Both Gnutti and Magistroni cranks were a three arm pattern with the same standard bolt circle diameter.
They were often used in conjunction with the French made Simplex chainrings.
Simplex had these three simple bolt-on adapter arms. (Picture below.)
Gnutti’s quick release hubs were a copy of Tulio Campagnolo’s original idea, I’m not sure if the patent had run out, or they were made under license. The hubs had a chromed steel barrel with aluminum flanges pressed and swaged into place. (Pictures below.)
Finally this Magistroni headset (Pictured below right.) intrigues me, it is quite an engineering masterpiece. How did they get the “Magistroni” name around its circumference?
It would not have been cast, a casting would not work as a bearing surface.
Stamping not possible around the complete circle. It would not have been engraved or pantographed, too costly.
Knowing a little about engineering practices of that era, I believe the lettering was rolled on.
Probably done while the bar stock was in a solid piece, before the headset cup was shaped in a lathe. The bar would be turned slowly and a rotating die with the lettering in reverse pressed into it under great pressure. If anyone else has any alternative theories let me know.
Also note the teeth machined into the top of the bearing cup, with a lock ring with matching teeth. After loosening the top nut, this would allow adjustment by hand, one notch at a time. The lock ring being keyed to the steering tube would prevent the bearing cup from turning as the top nut was re-tightened.
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Reader Comments (6)
Campagnolo did not hold the patent. Fratelli Brivio (FB) held the patent and FB made Campagnolo hubs until FB’s patent expired circa 1951, then in about 1952 Campy broke with FB and made it own hubs (gran sport). Tulio held the patent for the quick release skewer. Gnutti made similar QRs marked under license (in Italian) for some years. Love those old parts and brands.
FB made hubs under its own name, for Campy and Simplex, and private brand labeled like Bianchi, Maino, Visconti etc etc. Campy probably killed these other players.
I too am not aware of a process to support the raised letters around the perimeter. My only guess is lost wax process. Not having one, it is difficult to know from examination.
I purchased a 1973ish Bottecchia Giro d'Italia which has a Way-Assouto headset. it is unique in a number of ways. http://velobase.com/ViewComponent.aspx?ID=D24236D6-2A9B-4AF9-A55C-27C323D76FCC&Enum=111&AbsPos=223
artwork
This headset looks to have been produced through Die Casting. In the Machinery’s Handbook, in Die Casting “Figures and letters may be cast sunken or in relief…” Quite elaborate designs can be cast in many materials including steel and aluminum, with very close tolerances. The result here is embossed lettering all-round the steel headset.
After casting, the bearing race was then machined into the cup to achieve accurate alignment as well as a smooth finish (grinding may also have been used here).
Also, the circumferential relief letters do not appear machined. That process would have been not only prohibitively costly, but probably impossible.
I don’t think the letters were formed, or rolled into the metal with a knurl-type tool, as Dave described. Knurls, such as straight, diagonal, and diamond, form, or roll, a consistent pattern around the part. This requires extreme, consistent, pressure into a very hard material, here in steel. Steels and alloys are the hardest I have knurled, so we used two knurls, 180 degrees apart so pressure was equal on both sides. We even cut straight knurls with a side tool, an end mill rotating with the spindle indexing, especially in 321 stainless and harder alloys. But only CNC machines can perform this operation.
So I don’t think a single “knurl” with letters engraved into it (as well as background patterning), could have done this. The pressure would have been tremendous and you would have to time your exit perfectly so you didn’t run over the letters again, such as in “double knurling”.
Thus I think it was die cast.
Unless we see actual manufacturing processes from the maker, we can only ask ourselves: “How would I do it?” Or applying Occam’s Razor, which hypothesis has the least problems.
I don't see any any parting lines for a casting of any kind. Plus, there would be some draft angle on the letters. Not a clos e enough pictures to show if there is a draft angle or not. I still suspect lost wax.
“(Precision) Investment casting uses an expendable pattern, usually of wax or injection-molded plastics. Because the mold is in one piece, undercuts, apertures, and hollows can be produced easily.”
“Precision investment casting is similar in principle to the “lost-wax” process that has long been used in manufacturing…”
“Die castings are used extensively…Lugs and gear teeth are cast in place and both external and internal screw threads can be cast. Holes can be formed within about .001” inch or even less…and the most accurate bearings require only a finish-reaming operation.”
-Machinery’s Handbook, Industrial Press
The manufacturing process used to produce this headset was most likely a type of casting: either die-cast, precision investment casting or “lost-wax” casting. Since bottom brackets, lugs, and other bicycle parts have been cast for years, I think this was the only economically as well as technologically feasible way to produce these headsets.
It is secondary machining that finishes many cast pieces, such as in this case bearing race surfaces that also assures proper alignment. Also, most parts are tumbled in various media to achieve proper finish.