top cap size
I took my frame to the bike shop for threadless headset installation but, having no stem yet, I told them to leave the steerer uncut. I got the frame back and they gave me a different top-cap and star nut than the one I gave them. The steerer is 1", what should the diameter of the top-cap be? Will some top-caps only fit well with certain stems?
Most stems run 1 1/8 so you need to use a shim. Thus, your top cap would also need to be the 1 1/8 inch model. Not sure what your wrench's logic was, but this could be one explanation.
I agree with capwater. Also, if your fork has a carbon steerer, you need to use a compression plug rather than a star nut.