I'm building up a Chinese carbon AC024 cyclocross frame with mounts for disc brakes. The threads in the frame (they look like an aluminum sleeve in the frame) appear to be 6mm but when I try to insert the bolt, i get about a 1/4 turn and it stops.
Now, I can't get a pitch gage in there but I don't think there is such thing as a 6mm bolt with anything other than 1.0 pitch. That means that, perhaps, during the build, they did something like run a tapered tap just part of the way in.
I tried to contact the seller (Miracle) and see if they would verify that the threads should be 6mm and 1.0 pitch but no avail.
I'm tempted to use a 6mm bottom tap but I'm also aware that if I'm wrong and screw it up, I'm out about $500.