What size of branch can you cut with our branch (concave) cutter? You might think that if the blade lengtl is 25mm then you can cut a branch o the same thickness. You would be mistaken. To cut safely and without damage, branch thickness should be a half to one third of your blade length. For instance, if your blade length is 25mm, then you can cut a branch of between 12mm to 8mm thickness. However. it is important to note that these sizes apply to branch (concave ) cutters, and does not include scissors. You cannot cut branches of this thickness with scissors.