Had splitting headache - used that time cleaning house.
Felt better two hours ago and made it into garage. Second part turned out right, first was exactly one millimeter too big on spigot.
Threrapeutical really. This is for small taps. 2,5 mm tap as a scale and the thread die OD is 16 mm.
Bigger tap is short M12 tap to give some scale.
M4 crub screws are way too long, they are thre just to check the fit. Need to get shorter cone point set screws.
Pekka