Made some PCBs that came unbeveled on the edge connector, even though I requested the service, so instead of manually freehand a bevel, I made a jig to evenly bevel the edge on standard 1.6mm thick PCBs.  It uses sandpaper and works well enough for me. Just wear proper PPE since you're sanding PCBs. I just sanded in front of a fume extractor since it was convenient and that worked really well. The lower the grit, the faster you'll get results. 

Things you'll need:  Just sandpaper cut to size to fit and glue in the handle.  I just used standard superglue and that works well.  
*Tip: If sandpaper gets clogged, just use a brush or standard eraser to clean it. Good sandpaper can last a long time if you just clean it.

1. Test fit the PCB into the jig.  It will be tight the first time (for me anyways) but will fit just right after the first couple fit.
2. After gluing the sandpaper to the handle, test run through the beveler to make sure the handle slides easily.  You'll want to run this a few times to “level” sanding area. Clean the sandpaper as mentioned above. (remove any stray filament that may have come loose after the initial sanding to level the base). 
3. Now you're ready to test a few PCBs to bevel.  You should get the results as shown in one of the pics. 
4. If you want to bevel the other side, just flip the PCB around. 
5. The handle can be flipped to use the other side of the sandpaper to make the best use of it.