My reply moved from
http://www.thorncycles.co.uk/forums/index.php?topic=6141.msg36317#msg36317, where it was off-topic.
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How do these Drillium rings hold up?
Amazingly well, Jawine, provided they are done right. I've drilled a number of 'rings myself, including those on my father's touring bike and sister's gorgeous mixte and a number of mine (pic below) and the key is to stress-relieve the edges with a chamfer bit or slightly countersink with a larger bit. the other secret is to place the holes carefully, and if there are many, to avoid corners and such in patterns that could lead to cracking from hole to hole.
If the hole-drilling and metal-milling are done safely, the weight saved is negligible.
I viewed drilling as a chance to hone my machining skills back in the mid-'80s, and I also thought it looked pretty, especially when the sunlight caught the chamfers. I took care to put reliability over light weight, and drilled only smaller chainrings; I've seen large ones with too many poorly placed holes fold in two on finishing sprints during races back in the late 1970s. A lot of the drilling done then was taken to extremes and became not only crazy-light, but crazy-fragile, too. I refused some requests by others simply because the parts would not have been safe After. For example, I would never, ever, ever have drilled handlebars, stems, seatposts, cranks, or brakes for actual use. Derailleurs, chainrings, and cogs, sure, and a few brake lever blades but only if they were left structurally sound.
I also made my own bash guards back in the day; a few are shown in the composite below. I enjoyed engraving stems, seatposts, and cranks and remilling cranks, but that is a topic for another day. A picture of an early Deore crank I remilled and polished in the late '80s is shown below as well. Baking enamel into the drillium and millium was the next level in the artform, and I made a few of those also, particularly wrt custom ball-head-milled engravings.
If you're interested in the whole drillium craze, here are some links:
http://www.classiclightweights.co.uk/extras/drillium-extras.htmlhttp://www.velo-retro.com/peterjohnson.htmlhttp://prollyisnotprobably.com/2010/09/the-making-of-the-affinity-drillium-212/http://www.flickr.com/photos/54616231@N04/collections/72157631105870544/http://velo-orange.blogspot.com/2012/07/drillium.htmlhttp://www.tearsforgears.com/2005/09/drillium-info.htmlhttp://bicyclepatents.com/a-bad-case-of-drillium/1293/http://biciak.blogspot.com/2012/07/pantographing-and-modern-millium-and.htmlSome drillium/millium is fine; other kinds are Art, and not all art should be ridden. Except for shoes. Mine are made of drillium/leather. See:
http://www.thorncycles.co.uk/forums/index.php?topic=3896.msg18979#msg18979Best,
Dan. (...who thinks just because you can, doesn't mean you should).