by watlingboy » Wed Apr 13, 2016 1:29 pm
Rol-A-Tops never had nails in the front and back edges of the base like Mills and others. Instead they have a long carriage bolt that runs through the base front to back. On the front are or were dowel plugs which covered up a hole where a round brass nut was screwed tight to the carriage bolt and that's where the problem begins. Wood is always moving, expanding and contracting slightly. The top of the base is sealed and the bottom is left unsealed. The wood can no longer expand and contract because of the carriage bolt which isn't a problem until the bottom comes in contact with moisture. The wood can't move and therefore cups and cracks. The amount of cracking or splitting depends on how wet it got and the humidity and temperature of the location. Southern states are much worse than others. I'm confused by you saying you have a carriage bolt head at both ends. Should be a carriage bolt head in the back and threads in the front for the round brass nut. Those two nails in the bottom, going into the sides were done at the factory and not by someone else. I use those nails holes to make sure I have the sides in exactly the same spot they originally were, otherwise your back door may not fit correctly. The back edge of the wood base over the years get compressed from the tight carriage bolt and that is why the bolts get loose. The bolt was only there for security and no longer needed for that so I remove the spline in the bottom, cut the bolt to 6 or 8 inches, put glue in the spline groove to hold it in place and reglue the spline. Whatever you do, don't put the brass nut back on and tighten. Replace the dowel plugs in the front edge and the base now looks completely original without the risk of it splitting again.
Watlingboy