I inherited this lovely walnut board, 16.25″ wide, 24″ long. Unfortunately, it was starting to crack in two places. I repaired the larger crack with an ash bowtie (aka butterfly), which I rounded to echo the grain of the board. It it is the full thickness of the board. In the image you can see how it has pulled the crack together next to it very tightly, so that it almost seems to disappear. I tried a different repair on the smaller crack, an end-grain insert, also ash, that has two wedge shaped legs on the inside. I’m hoping this will keep the board from splitting more, though it didn’t seem to affect the appearance of the current crack.
In both cases, I drilled the walnut to remove the majority of the wood, then cleaned it up with chisels. Working on something I own is a pleasant change from the ethical constrictions of performing conservation work on wooden book boards. It is also a good chance to experiment a bit, since I will be able to monitor any changes. On a related note, a version of the article Alexis Hagadorn and I wrote, “The use of parchment to reinforce split wooden bookboards, with preliminary observations into the effects of RH cycling on these repairs” (Journal of the Institute of Conservation, Vol. 33, No. I, p. 41-63) should be available soon online at Columbia University’s repository. I’ll post a link when this happens.