T-Mar is absolutely correct, i hope that my previous response didn't cause more harm than good. I knew what things were supposed to measure but i wanted to be doubly sure that what i said was correct so I wouldn't put my foot in my mouth so i measured everything directly. 1" steerers and stems, 1 1/8' steerers and stems, and head tube diameters. Unfortunately the calipers i was using read a bit differently than my good pair which i can't seem to locate, and the parallax error was such that everything turned out to measure exactly one dimension down. So to conclude, in trying to help I probably confused more than anything. I do however think i might have guessed your problem:

Make sure you read the caliper to the 0 mark and not to the edge of the blade, or if yours is like mine you'll be off by about 4 mm.