I needed to slice some pieces of wood to be exactly 1mm thick. I initially did this with a scalpel but it was time consuming. I instead made this tool which you fit a razer blade into and use the arm to press down and cut through the object. I have 1/2/3/4/5mm spacers, you can print out multiple to make the correct size that you need.
4 x M3 nuts and bolts, must be over 16mm
3 x M4 nuts and bolts, must be over 16mm
1 standard razer blade