add f3d

README.md

 # Fabricable Rotary Bearings
 
+## CAD is here
+
+[Fab Cross Roller Bearing](/cad/Fab_CRB.f3d) follows directly on Laimer.
+[Fab BLDC](/cad/Fab_BLDC.f3d) contains a bearing that uses balls, not rollers, in a cross-type. 
+
+## What it is
+
 Largely following on [Christoph Laimer](http://www.laimer.ch/)
 
 What we want is a large diameter bearing that will handle some big off-axis loads. In 'industry' we use Cross Roller Slew Bearings: