I would also add - do NOT cut or file or otherwise remove any brazed-on frame fittings, hangers, etc., from a frame being converted to fixed-gear. If you are fortunate, you will be able to score something early enough from the era of minimal braze-ons. My current conversions include a '73 Raleigh Competition, which has a pip to keep clamp on shifters from sliding and cable housing stops for the rear brake on the top tube and a chain stay cable stop for the rear derailleur. My other conversion is a '71 Gitane TdF, which has a pip on the downtube and nothing else.