Before the tube is clamped by the jaws of the flaring bar, the 11/48-inch-thick heel of the flaring adapter (shown) is used to establish the 11/48 inch of tube that protrudes beyond the bar. This is a critical step. Too much tube will cause the flare to collapse or become cocked off center. Insufficient protrusion yields an incomplete flare (junk). Use the heel of the appropriate-size adapter as your guide and you won't go wrong.