Seam construction for papermaking fabrics

A method of making a seamed papermaking fabric having a multilayer base fabric, comprising the steps of

• endless weaving a tubular belt fabric having a
• predetermined width measured between opposed axial edges of said tubular belt,
• predetermined length measured circumferentially around said tubular belt,
• predetermined weave, and
• predetermined thickness;
• flattening said tubular belt to form a base fabric of substantially twice said predetermined thickness with opposing portions of the sidewall of said tubular belt being closely adjacent one another and said flattened tubular belt having a flattened length between lengthwise extremities thereof of about half said predetermined circumferential length;
• inserting at least one helical coil seaming member between said opposing sidewall portions at each respective lengthwise extremity of said base fabric, with the helical axis of said seaming member extending transverse to the lengthwise direction of said base fabric and the coils of said seaming member extending through spaces between adjacent machine direction yarns and supportably engaging said machine direction yarns to support said seaming member against force applied outwardly of said respective lengthwise extremity of said base fabric;
• and
• joining together said opposed lengthwise extremities of said base fabric by interengagement of said coils of the respective said seaming members and insertion of a pintle member axially through said interengaged coils to form a seamed endless fabric of substantially twice said predetermined thickness.