Abstract: A heddle frame includes a top rail and a bottom rail connected at their ends with end members to form a rectangular frame. An adjustable center brace assembly extends between the top and bottom rails, and includes an elongated brace extending through the top rail with a bottom end adjustably and lockingly engaged with the bottom rail. The brace may have a multi-sided head at the top thereof configured to be engaged by a conventional driving tool. A locking block is disposed over the multi-sided head and is a removably attached to the top rail. The locking block has a recess defined in the underside thereof with a width corresponding generally to that of the multi-sided head for rotationally locking the head and center brace. The head of the brace has a width so as not to extend beyond the sides of the top rail, and the head can be rotated with a conventional driving device without removal of the heddle frame from the textile machine, or interfering with adjacent heddle frames.