Over tightening the bow to avoid playing other strings unintentionally is really not good. 🙂 So first, let’s talk about the bow and how tight the bow hair SHOULD be. Notice the stick of the bow has an inward curve. This should always be maintained. If you regularly overtighten the bow hair, it may stretch the bow hair permanently, and therefore, force you to overtighten so the stick doesn’t touch the strings as you play. If this is the case, its time to buy a new bow. Or, if you have an expensive bow, you should get it rehaired and never overtighten it again.
The bow hair, when tightened, should be about a pinkie’s width away from the stick at the middle of the bow or at the closest point. If you need a couple more turns of the screw, that is OK. Be sure to loosen the bow hair every time you put it away. Every Time!
Now about hitting adjacent strings. This is one of the core beginner achievements and you need to practice getting a clean sound, knowing where your strings are, and not hitting other strings. You shouldn’t avoid mastering this ability by overtightening your bow. I recommend open string practice to become familiar with string locations and how much room you have before you hit the next string. In the pieces that you play, if you hear that you’re hitting other strings (I call it ‘space junk’), you should bring that unit out of the music and look at what is going on. Take away the fingerings and practice just the bowing with open strings. Work that out first. Then put fingers back in.
If you continue to have problems with ‘space junk’, there are other things to look at to make sure you are not working against an impossibility. A lot has to do with the curvature of the bridge. Also, how the bow arm is working. Each issue should be taken up and examined to be sure you have optimal chances of playing strings without hitting other strings.
I’m here to help you work on these issues if you want to submit photos or videos or describe in more details.
Here’s a bow in a ‘ready to play’ tightened state. The bow on the top is correct. The bow on the bottom is too tight.
Here’s a good curvature of the bridge. Notice the E side is lowest. The curvature of the bridge enables you to change the bow angle to hit strings either together or individually. If the bridge is shaved down too flat, often we have problems hitting other strings. Also the strings are evenly spaced apart. If your strings are not evenly spaced apart, you may have trouble hitting strings individually.