How/How much to Tighten the Violin Bow?

For a beginner, it is very important to know how to tighten the violin bow, or how much to tighten it.

Rules for Tightening
 1)Turn the adjustment button right to tighten the bowhair, left to loosen it.
 2)Place the end of a standard pencil between the bowhair and stick, at about the middle of you bow. The tension is good when the pencil just fits in the space. That means that the hairs and the stick should both slightly touch the pencil. Until you get more familiar with this technique, it’s a good idea to keep a short golf pencil in your violin case.

Here we attached two videos, might will give you any help.