The following information is important when you get shaft ends turning from rolled thread ends done.
To run a sleeve bearing pure clean on a shaft end TR20x4 a diameter of 14.00 to 14.50 is to be reversed. (Upper shaft)
The middle shaft on the picture below is obtained by turning the diameter minus the pitch minus 1 mm. For example: TR20x4 a tap of 15h7 passing plane is 98% of the surface.
The lower shaft on the picture below is obtained by turning the diameter minus the pitch. For example: TR20x4 a shaft end 16h7 of the fitting surface is 80% of the surface.
Spindels met tappen