I had one of the first-run Regina CX freewheels, which did break. I was told by Ted Ernst that the 'bad' CX freewheels had a body that was too thin near the top (below the outside cone) and when the too-thin bodies were heat treated as part of the manufacturing process, they became brittle and then fractured. The fracturing problem was addressed fairly early (within a year) and later CX freewheels were more durable. I had used at least three CX freewheels subsequently, and none of the others broke or gave me any problems.
I recall that the later-made Regina America freewheels had even cog spacing, to support their use in indexed derailleur systems. I'm pretty sure that the later-run CX and the America bodies are the same.
Here is my Regina CX fracture story:
My Bad Day On The Bike [March of 1983(?)] started with my getting a road debris scratch on my almost-new prescription sunglasses, was followed with a tire-killing slice on my rear Michelin clincher tire, then was pleasantly interrupted by the generosity of an unknown rider who lent me a tubular (to install on my Mavic G40 clincher rim) so I could ride sloowwwly to a bike shop and buy myself a replacement clincher tire. That so-called pro bike shop selling me my clincher tire told a load of bull***t to the tire-lending cyclist, saying that I ruined his tubular (which I didn't) by installing it on a clincher rim. After my generous riding companion and I parted company, about half an hour later, THEN my Regina CX freewheel body fractured and spilled out all of the ball bearings on the ground, leaving me stranded, 10 miles from home.
I glad that the president of my local racing club was home, so that he could send out one of my riding club buddies to rescue me.
At least I got a free replacement freewheel, under warranty!
Andrew Gillis (no more broken freewheels, ever, in Long Beach, CA)