This 1/8" provides space for the coverings.

After the frame is fitted, it is covered with 3" webbing tacked firmly to the upper side.

The webbing which goes back and forth is interwoven with that which goes from right to left.

Over this is stretched and tacked (also to the upper side) a piece of unbleached muslin.

A second piece of muslin is tacked to the back edge and part way along the side edges, leaving for the time the corners unfinished.
In the pocket thus formed horsehair or other stuffing is pushed, care being taken to distribute it evenly and not too thick.