I have a small print area so I had to print the chess set at 80% of original. As a result, I had to get creative with the weighting of the base. What worked for me was a 5/16 inch nut that I epoxied into each base. Still, I wasn't able to keep the pieces from falling over. I saw in comments that one person was able to sand the base and get the pieces to stand up but it seemed like it would be tough to sand each base just right to keep the pieces standing vertically. Instead, I modified the base to add a small flat region that is close in size to the flat region in the center of each square. Now each piece stands nicely vertically but can still wobble a bit. You can check out my remix to download a modified STL of the base. Finally, I added a wooden base to give the board more heft and make it rigid.