Not always it is possible to level precisely the end of a ruler with a preparation end face therefore in such situation it is better as speak, to offer zero. Combine the following serial division with an end face and note the size according to it.
You accurately cut all details, achieved density in all connections and now are ready to be engaged in assembly. But before opening a bottle with glue, surely carry out trial dry assembly (without glue). Collecting a product, define, in what order it is better to connect details, how many clamps will be required for dense compression of all connections and as it is better to place clamps that there were no distortions.
To draw a thin line parallel to a preparation side, use a surface gage. The nest contour marking on a rack after definition of provision of the end of a crossbeam is shown
The sharp knife leaves the thinnest line, providing high precision of a marking. In certain cases the profound line becomes also launching site for a chisel
Applying a rasp, a chisel or any other tool to removal of material, do not hurry and regularly check result, connecting details.