I haven't posted here on ages as I've been riding road bikes now for the past five years or so, but my brother has taken over my fixed gear interest in my absence. For years we've been slowly converting his 1970's Mercier. Years ago, I shaved off most everything but he wanted to go further.

I cut the dropouts off, added a little metal on the seat stays and then just flipped the old dropouts (after re-shaping them a touch) and welded (not braised) it all together. It is stronger than it was before the conversion and looks great. The geometry is almost identical to the original (which was accomplished by lengthening the seat stays). I added a new brace across the seat stays as his was badly crushed from an over-tightened rear brake and fabbed up a third little "devil tail" to match the other two already on the frame.

I sanded an polished his cut aluminum drop bars (cut up to bull horns), the old left over SR stem and his cranks to a mirror finish.

I then soda blasted the frame and etch primed, colored, then cleared it. We kept the original fork as the likes the way it rides.

Photos below. I just wanted to show that the conversion CAN be done properly, but it requires a fair bit of skill and many hours of labor.

This bike is made entirely from left over parts and was put together for well under $300 I believe. Its just lots of time and labor.