angle flange

[GiGa]

I'm trying to make a plate fitting. This is a round-table plot. on the square side I have to put some "flanges" but, for having them parallel to the "rest of the world" I have to set a corner of 0.05xxx (recommended by a quota)... setting this angle however the "flangia" function returns me error... I can set the angle to 0° or greater than 0.26° (recommended with various attempts)... in practice, the range 0°~0.26° is not usable... shows the preview, but then

sheet: unsuccessful flange modification.
raccordo.ipt: an error occurred during the update.
modeling error in asm. redefine inputs.
processing calculation failed.

Is there any parameter in sheet styles or any tolerance on which to act?

 

[GiGa]

On another side, with an almost equal angle, the flange is made... boh... probably there is a rule for explaining that prevents me from going on: mad: