Parametric bearing housing

This is a parametric design of a bearing house with pockets for hex nuts. The design is based off of a non-parametric design of a bearing housing of Instructable user [liquidhandwash](http://www.instructables.com/member/liquidhandwash/) that is a component of his [3D printed CNC mill](http://www.instructables.com/id/3D-printed-CNC-mill/).

The overall shape of the housing is a box determined by the parameters *Width* and *Height*. The cylindrical recess at the center of the box keeps the bearing in place and is determined by parameters *Bearing Outer Diameter* and *Bearing Height*.

The difference between *Height* and *Bearing Height* determines the thickness of a "flange" at the bottom of the recess. Additionally, the flange has a cylindrical opening determined by the *Flange Inner Diameter* parameter.

The housing is intended to be fastened by means of four bolts and pocketed hex nuts. The dimension of the bolts is determined by *Bolt Diameter*. The center of a bolt is offset