This lock ring has a lip that overlaps the top of the fork head tube. I can see that my hammering effort in the top groove has dimpled the lock ring into the fork head tube. If that makes sense? I think my next step will be to cut the two grooves down to the lip over the fork head tube. Hopefully that will give me more grip on the lock ring itself as well as relieve some stress holding the thing on & save the headset.