Drilling The Chain Ring
The odyssey began with a 52T Sugino factory-drilled ring which I planned to use as a template to drill a 52T Campy Nuovo Record ring.
I clamped the rings together, with the Sugino on top, using a couple of chain ring bolts to make sure that the rings were properly aligned.
I clamped both rings to the edge of my work bench and I drilled through the holes of the Sugino into the Campy.
Unfortunately the size of the outer circle on the rings did not match, and the holes were not centered on the Campy ring (they were too close to the outer edge).
I removed the chain ring bolts and I tried to find the correct position for the Sugino ring over the Campy ring by trial and error.
I came pretty close to getting the holes right in one of the sections, but in the end the I used the first holes I made as a template for a Campy 53T (the one I have on the bike now). The holes were too close to the outer edge of the 52T, but they were perfectly centered on the 53T - which was a good thing because the only extra ring I had on hand was a 53T.
I then proceeded to drill the holes for the circle pattern. First I marked the location of the holes with a black marker. And this is where I wish I'd known about using a countersink bit to start a hole, because since I did not have a drill press, I had a hell of a time drilling my holes where I wanted them. Eventually I managed to get one semi decent-looking circle pattern, and I used it as template for the final ring.
This is what the 53T ring looked like after I completed the drilling:
The next step was countersinking/counterboring the holes, which turned out to be the easiest part of the whole job. Using my trusty old cordless Makita, set at the lowest torque, I applied very light pressure and used a very slow drill speed. It only took about 5 or 6 turns of the bit to do each hole.
The countersinking is not perfectly even at all the holes. For that I would need a drill press. But if you just want the countersinking to look good, you don't need no stinking drill press :)
The final step was to drill and countersink holes along the inner web - because that's the way Eddy had it! Using a countersink bit to start the holes for the inner web, I managed to place them right where I wanted them, and that finally resulted in the not-great-but-presentable ring you see on the bike now.
Now that I know the trick to starting a hole where I want it to be, I'll have to do another ring and improve the positions of the holes in the circle pattern. Thanks to Tam Pham I have a couple of nice used Nuovo Rings to work on.
Sadly, I butchered the 52T Campy ring too far to ever use it on a bike again - no self-respecting poseur like myself would be caught dead riding such a ring. But the ring's beauty was sacrificed for a worthy cause, and it can still serve as a template and "testing ground." In fact, this is where I'll try my hand at an improved circle pattern.
This is what the sacrificial ring looks like now (notice the three holes on the left side of the inner web - I used these as template for the final ring) :
By the way, this is what a single-flute countersink bit looks like (my thanks to Jay Sexton for sending me a "starter set" for free):
The bits are available in different diameters and head angles. The bit I used was 1/4" diameter with a head angle of 90 degrees. You can get more information and just about any bit you could want from McMaster-Carr (this link will take you straight to the countersinks page).