A tenfold end mill holder for sizes d6 / d8 / d10 d12 / d14 / d16 / d18 / d20.
Originally the holder was designed with Soldiworks, it could be parameterised via global parameters for any diameter and number.
Unfortunately, I no longer work with Soldiworks and only have the .step files, I have never tested myself whether the step. files can also be parameterised.
The author hasn't provided the model origin yet.