Identifying a crack in a wood instrument

November 11th, 2013 by

Repair technician Eric Anderson offers some thoughts on identifying when you have a crack in your instrument.

First, it is important to know that it is sometimes easy to mistake a crack for wood grain or grain for a crack. In order to avoid this it is a good idea to do your inspections with the help of a magnifying glass or loupe. However, one is not always needed.

Where cracks are most commonly seen:
In general, the majority of cracks are found towards the top of the upper joint of an oboe or clarinet, where the wood has been removed for sound (tone holes) or mechanical connections (posts for key rods). These cracks are generally formed due to temperature fluctuations and moisture causing an expansion of the wood. On an oboe the location where I see cracks the most is between the two trill tone holes. Many times, this may extend up towards the crown, down into the B tone hole, or both. The reason this is the most common place to see a crack is due to the relatively close distance between the two trill tone holes, and consequently it is the place of least resistance. Also, I recommend looking at the 3rd octave tone hole (when present), or through any of the posts in that area.

A Note from Jeff Marshak, Oboe specialist

“When/if you experience a cracked oboe, depending on the nature and severity of the crack, there are few things to be observant of in the way your instrument plays.  In most cases, a surface crack on an oboe will not affect the playability of the instrument and can exist without affecting the seal.  Cracks that are more severe that extend into the bore will be more problematic.  The first sign of a potential crack can be heard/felt in the low notes, specifically on F#, F,  & E.  The instrument can feel stuffy and unresponsive throughout the low register.  This is a result of the instrument not sealing in the top joint.  If your oboe is playing fine one day and suddenly notice issues in the lower register it can potentially be due to a crack.”

Other less-common places to spot a crack:
Cracks rarely form on the back side of the instrument where there are no holes, though I do see it intermittently. On occasion I will even encounter an oboe lower joint with a crack. When it does, it is usually a small ½” crack located over the socket, and running between the socket band and the G tone hole. When this crack is found, it is usually in the spring or summer, and is due to the expansion of the wood. This differs from the more regular cracks found in the upper joint in that they are caused by mechanical stress versus moisture and/or temperature. A tight relation between the tenon of the upper joint and the socket of the lower can result in a “split” in the wood. This can also be seen on the back side above the thumb rest.

Clarinets also experience cracking as well. Again, this is most common near the top portion of the instrument’s upper joint. Looking around the trill tone holes, posts, or the register key vent is a good place to start. The barrel is also a common place for cracking.

The sooner you spot a crack the better. Bringing the instrument to a professional to be pinned and glued at the first sign of a crack will greatly decrease the risk of it growing and turning into a more costly repair.

Midwest Musical Imports
Repair Department
Eric Anderson & Matt Reich

 

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