For small custom builders of the past, most parts packages were supplied by a very small number of parts makers. Most bikes built in the 70's were built up with parts made by the Italian parts maker Campagnolo.
So, some of these small frame builders, who wanted to make their finished bike look more "theirs" and to differentiate their complete bike from another maker who used the same parts, began contracting out to machinists to mill their logos onto the parts they did not make. This produced a complete bike with a look that was customised by the frame builder to be his own. This was called pantographing and, because of the extra cost involved, usually was applied only to the top models of the builder's line.
These pantographed bikes are sought after by collectors because they are more unique and rare than non-pantographed bikes. Plus, they look cool too! :)
Now, we switch our story to the US in the 70's when crazy American racing cyclist were trying the make their bikes lighter by drilling holes, to remove material, in every part on the bike. Below is a chainring drilled to make it lighter.
This practice faded out when many of the owner-drilled parts failed during the course of a race.
But there was also an aesthetic aspect to the drilled parts, similar to pantographing. In recent years, the judicious drilling of parts has been revived solely as decoration.
I have become an enthusiastic evangelist of decorative drillium/millium as a new cycle art form. A talented individual can add considerable style and color to a standard bike by creating a set of parts that are unique for that bike. There are a number of such people plying their skills and one such maker is Jon Williams of Oregon (Drillium Revival on Flickr). Jon has created two unique sets of parts for two of my frames. Each is different and complements the frame's paint and character.
1973 Colnago Super with Drillium parts made by Jon Williams.
Here, Jon created a set of parts in the style of early Colnago pantographica. The Colnago logo is a Flower or Club symbol. He made the club by drilling three holes together as was done in the very earliest Colnago pantogaphing and applied it to the seatpost, stem, derailleur, and chainrings to form a coherent set of parts that work together.
For my 1974 Carlsbad Masi, I wanted to use the Faema team colors of the style used when Eddy Merckx rode for Faema. Jon keyed off the Italian flag colors of red, white and green to complement the Faema color scheme.
Jon has a talent for coming up with unique and different schemes for each bike. His Flickr images are well worth a look:
He can be contacted at DrilliumRevival@Yahoo.com