I'm at the point in my split top Roubo bench build per the Benchcrafted plans that I need to cut and fit the short rails of the base. These are the cross pieces that will support the two halves of the top, which are mortised for the leg tenons. Since these substantial top pieces are fixed at the front and rear of the bench by the leg tenons, any wood movement will cause the gap in the middle of the top to change width.
My top is laminated from Douglas Fir, flat sawn boards, with rings oriented more or less vertically. Per the Benchcrafted plans, the gap should be 1 5/8, while the gap filler is 1 9/16. That only leaves 1/16th of an inch for wood movement.
Is this really sufficient? I live in Oregon where the summers are dry and the winters humid.
Brent