ThreadCreater nut and bolt

Question on Thread Creator
I created Nut and bolt both with diamter 8 mm. Then I added ISO-Thread, tried both 1 and 1.25 mm pitch. After exporting to stl and printing, there is no way that both fit. Should the diamter for inner and outer thread be different?

Question on Thread Creator
I created Nut and bolt both with diamter 8 mm. Then I added ISO-Thread, tried both 1 and 1.25 mm pitch. After exporting to stl and printing, there is no way that both fit. Should the diamter for inner and outer thread be different?