Antique Yellow wood restoration

Dennis,

The first thing to do is try and determine whether the splits are seasoning checks, or cracks due to some kind of cross-grain restriction.  Generally, seasoning checks are caused when the furniture is built from incompletely dried wood that dries too quickly when brought into a dry environment.  Usually these will appear as a number of small cracks, on end grain surfaces, some of which may extend for some distance  along the face of the board.  These checks can not generally be clamped back closed.

A crack caused by restricting the normal seasonal movement of the wood most often shows up as a single split that extends for some distance across the board.  Sometimes the stress is relieved by two or three splits appearing, more or less equally spaced across the width of a broad surface, like a tabletop.  Sometimes these splits can be repaired, but before a successful repair can be made, the issue that caused the splits to occur must be remedied.

Seasonal splits are caused by some construction technique that restricts the swelling and shrinking that wood undergoes from summer to winter.  If the table top is glued or screwed tightly to the apron beneath it, that could be the problem.  If there is a batten or breadboard glued across the width of the top, it can easily cause a split to develop.  Additionally, if the piece has been moved from a generally moist (humid) environment, into a much drier one, it can precipitate a crack in a piece that previously had no problems, maybe for many years.  Think of a piece moved from England or Seattle to Arizona. In any case, the means of attachment must be modified to allow for movement to take place, or the repair will fail. 

That may mean removing the top from its base, or the battens from the leaves, before you can glue and clamp the splits closed.  Then, before re-attaching a means must be devised for allowing movement to take place.  That could be as simple as "wallowing out" (enlarging) holes (in the aprons) for the screws before replacing them.  Or another, more imaginative approach may be needed, depending on your particular situation.

Ray