the one way ratchet teeth 10 thereby again locking the wear member 12 against forward movement relative to the support member 15 and retightening the wear member 12 thereon a second interfit tightening structure embodiment 40 is shown in fig6 11 and is similar in operation to that of the previously described interfit tightening structure 16 specifically the interfit tightening structure 40 see fig6 10 and 11 automatically functions to tighten a loosened interfit between a wear member 42 representatively in the form of a wing shroud telescoped onto a base member 44 welded or otherwise secured to a support member 45 illustratively in the form of an excavating bucket lip in response to rearwardly directed operational force exerted on the wear member 42 in this interfit tightening structure embodiment 40 however a set of one way ratchet teeth 46 see fig8 and is formed directly on a right side edge portion of the base member 44 as viewed in fig1 and cooperates with projections 48 on a metal contact block 50 similar to the previously described contact block 18 and secured with an underlying resilient member 52 by a bolt 54 within an internal side edge recess 56 of the base member 44 see fig6 as can be seen in fig6 and 10 rearward movement of the wear member 42 relative to the support member 44 caused by rearwardly directed operational forces on the wear member 42 ratchets it rearwardly to retighten it on the base member 44 and thus on the support member 45 to which the base member 44 is welded or otherwise secured if desired a second interfit tightening structure 40 not shown may be installed on the left side edge portion of the wear member 42 as viewed.