I use these blocks for nearly perfect leveling of my printer bed. I made them at 0.395" thickness but I do have to give each nut a half turn after setting the bed using these blocks. I believe 0.400" would actually make it perfect. (Surprisingly enough, at least for my printer" all three blocks are exactly the same distance.

• By request, I have added an STL file for blocks that will work if you are using the 5mm thick glass plate. (Please note I have NOT printed this item)