Crack Pinning

Crack pinning is the preferred method of crack repair for professional oboists. This involves the installation of small brass or stainless steel screws beneath the surface of the wood. The cracked wood may still swell and shrink a bit with the climate, even though pinned. The crack may open or close a bit over time, but will be greatly stabilized by the threaded pins.

After deciding the optimum location for the pins, a light punch mark is made in the wood to start the drill bit. I make the punch mark about 1/4 inch from the crack, depending on how deeply I wish to place the pin. The wood on an oboe is much thicker than you may realize (the bore is tiny). At first, it is necessary to drill straight in towards the bore to a depth of about 1/16 inch. This gets the bit started without it skipping off the curved surface. Then I gradually lower the drilling angle to aim the drill to a spot an equal distance on the other side of the crack.

I support the oboe against my bench and use an electric hand drill. Every other repairman I know runs the drill in a bench motor or lathe, and advances the oboe to the drill bit with both hands on the oboe. This requires the use of a foot pedal on/off switch to stop the pinning at the appropriate time. Not having much use of my legs from a childhood injury, I move the drill into the oboe, on the bench. Same thing, but backwards.

It helps the pin to form threads in the wood if it is heated red hot with a torch before running it in with the electric drill. After the pin is installed, it is flexed until it breaks off, preferrably below the surface of the wood. This is expedited by using a small dremel tool to open up the very surface of the drilled hole, so that the pin is supported further in while flexing it.

Any bronze inadvertently sticking out is carefully ground off with a small dremel tool before filling the holes with grenadilla sawdust and super glue. After waiting 20 minutes or so for the glue to thoroughly harden, the area is smoothed with fine files and succeedingly finer grits of sandpaper. Tung oil can be applied as a final finish.