This is why the mirror is such a great tool. What feels right isn’t always actually right. To get the bow to travel straight you have to move the arm in a C shape.

A bow skating in one spot can be caused by several things. One can be contamination from an oil in that spot. Another can be the player technique, as suggested by the luthier. Yet another can be a problem with the stick (warpage, a “hop” somewhere along the stick, a weak spot, or a knot that affects stiffness in a confined area). If the luthier saw an issue and you have also noticed that the bow is not straight in the mirror, I would incline more toward the luthier’s idea. You might check this with a different bow. Missing a spot when rosining could be a cause on a freshly rehaired bow, but once you’ve played it for a while and added rosin, that issue should be gone.

I’ve seen bows that were almost unplayable because of bad recambering or straightening. The bow would track smoothly until it hit the bad spot and then it would lose control and skip on the string. Sighting down the stick the spot was immediately visible, and by marking the spot with a China marker, it was easy to confirm that the skip began at that spot.

I had an issue with bow skating a few years ago. In that case the ribbon was discolored (maybe more translucent? I forget), so contamination seemed likely. I ended up cleaning it with alcohol. I forget which bow it was, but I think that solved my issue.

Ah, a new topic, great!
Being a “beginning” player, I too have issues with the bow skating at times. I believe it’s due to my bowing technique, not the bow itself. I’ve recently installed a mirror in my practice area and see I’m not always bowing at 90 degrees. In fact it seems like a real skill to do that. I watch YT videos of experienced players and am pretty amazed at the accuracy, or intention, of their bowing at 90 degrees. I’m hoping with much practice and attention I suppose it becomes more 2nd nature to accomplish this. Just trying to stay between the bridge and the fingerboard at 90 degrees is a big endeavor for me now. The mirror is helping.  And I've noticed I get better sound when the bow is 90 degrees. 

i practice(torture myself) with this occasionally. if i want to practice silently, i place the bow at the frog end then lift it off about 3/4" and keeping that distance away from the string while looking in the mirror to keep at 90deg to the string move down the bow and place the very tip of the bow on the string (silently). Then repeat tip to frog.

Then i go back to playing with an inch or two of bow, wondering why i just did that... it hurts...

I start every morning with a long tip to tip bow stroke on each string, then the 2 sets of double string low bows and then I press play on my practice playlist. I should probably visit the mirror again...

Straight bowing

This fella was my guide. Starting at 2:30 is where he gets into the nuts and bolts. I found the suggestion at 3 minutes to be most helpful. I used a coin where he talks about an eraser. Guaranteed to straighten you out. 

And he explains the 'optical illusion' I encountered - i.e., what appears to be 90 degrees is not, etc.

Amazes me every time how much it feels like i am pushing the bow away from myself at the tip of the bow to keep the thing at right angles to the string.

Edit: again i have to make sure my RH thumb does not invert/lock

quote:

---

Originally posted by ChickenMan

Straight bowing

This fella was my guide. Starting at 2:30 is where he gets into the nuts and bolts. I found the suggestion at 3 minutes to be most helpful. I used a coin where he talks about an eraser. Guaranteed to straighten you out. 

---

A lot of what he discusses is useful. His criticism of the doorway exercise is not justified, though, because both his explanation of upper arm movement in normal bowing and how to do the exercise are based on a significant misunderstanding of bowing technique. The point of the doorway exercise is to immobilize the upper arm to show that it shouldn't be moving in the bow stroke, only moving up or down to follow the wrist in string crossings. The upper arm should not be rocking back and forth--that's the very motion the exercise is designed to eliminate and it's one of the first things teachers work to correct in beginner playing. Done properly the exercise is very useful.

Another exercise that's quite simple but very useful is to simply play using only the wrist and fingers, not allowing the forearm to move. This forces the wrist to be unlocked. After doing that a while you can then bow using only the fingers. This helps to develop finger dexterity and fluidity in the bow hand. The bow is held, not gripped, so learning to make the fingers flexible and to get them working together in a fluid motion will go a long way toward developing a good bow stroke as a beginner.

Countless kids learn to "slither" up and down the stick as they're learning the bow hold, often before they even start to put the bow on the string. That motion helps to build finger coordination.

Todd's videos have been helpful to me too. It's taken me years to get this more or less sorted out to where I'm not doing the newby 'swinging saw' thing. One thing that helped me was to get the fiddle at a consistent angle to my torso, and then my right arm sort of knows where to shoot for. Hard to explain but it's all in getting your body attuned.

Rich, I don't think Todd is criticizing the door exercise. He correctly demonstrates how it prevents the right upper arm from angling backwards in the middle of the bowstroke, but also he shows that it comes forward again slightly at both extremes (top and frog). But since I guess at least 90% of fiddling is in that middle bow range, for practical purposes the upper arm is not moving.

quote:

---

Originally posted by JonD

Todd's videos have been helpful to me too. It's taken me years to get this more or less sorted out to where I'm not doing the newby 'swinging saw' thing. One thing that helped me was to get the fiddle at a consistent angle to my torso, and then my right arm sort of knows where to shoot for. Hard to explain but it's all in getting your body attuned.

Rich, I don't think Todd is criticizing the door exercise. He correctly demonstrates how it prevents the right upper arm from angling backwards in the middle of the bowstroke, but also he shows that it comes forward again slightly at both extremes (top and frog). But since I guess at least 90% of fiddling is in that middle bow range, for practical purposes the upper arm is not moving.

---

My point is that his illustration of the upper arm moving is an example of bad technique. When he described the arm bumping against the doorway and pulling away, that was evidence that he wasn't bowing properly, but he interpreted it as a natural occurrence and assumed it meant there was a weakness in the exercise, when really he had not performed the exercise properly or learned its lesson. Upper arm movement is one of the dead giveaways of bad technique

I remember learning the doorway exercise as a child, although the lesson was taught to me primarily through a different approach: my father would hold my upper arm with both hands like a vise to keep it from moving and he'd have me play that way until he could no longer feel any impulse coming from they area. Locking the upper arm really drives home the point that bowing comes from the wrist and fingers, not the shoulder. It's a somewhat counterintuitive thing, which is why beginners and poorly- or self-taught players so often bow from the shoulder. Like so many other aspects of playing, overcoming the innate inclinations and practicing good technique to the point (and beyond) that it feels natural is one of the biggest keys to getting a good tone. 

I imagine there are several schools of thought on this; watch Julia Bushkova's elbow here:

https://www.youtube.com/watch?v=-FD5fpfbd1I
 

It’s not that the upper arm can never move at all, just that the point of the exercise is to immobilize it to unlock the elbow and wrist so that the bow stroke is fluid and can follow a straight path. Bad arm movement prevents the bow from moving straight and makes it travel in an arc, which compromises tone. This is why beginning players struggle so much to draw an even tone out—as the arm swings back and forth, the sound is choppy and lacks finesse.

Here Zukerman demonstrates some fundamentals of bow technique as taught by Galamian. Although he mainly discusses the hold, you can see how little the upper arm moves when he uses the bow and how much the fingers are activated to control the bow:
youtu.be/zpnbyLeLVbQ?si=Yrr4Y9-ytN8X7SNH

Sure, I think we agree. I was just trying to dispel the notion that Ehle was demonstrating bad technique.