Bicycle Mechanics - Frozen headset lock ring

This is a 81 vista aerodynamic i plan to restore. The headset lock ring seems to be frozen in place. as you can see from the photo it can not be removed via a standard wrench. I have hammered around the two groves at the top with no luck. I am pickling it down with oil. Any ideas on a way to get this thing off?

It looks like a steel frame bike, but is the headset lock ring steel or aluminum? If steel then you need Liquid Wrench not oil. If it's aluminum then pour some ammonia on it instead-but don't breath this stuff!

Because aluminum expands with corrosion, you cannot loosen a frozen stem by force, so be careful applying force because many forks have been damaged by forcefully attempting to free the lock. Don't do it. If all else fails ask a skilled mechanic to grind it until it breaks through one side of the shell to extract the ring.

If the lock ring is steel, then allow a liberal amount of Liquid Wrench to penetrate overnight, then reapply then just try to wiggle it.

cut the sides of it.
maybe difficult.
try a dremmel tool. dont cut right into the fork steerer..just weaken it.
tap with a chisel to break through

The lock rings are steel. I should be more specific, Liquid Wrench is what i am using instead of oil. I will keep re applying. I was hoping to save the headset if possible.

Do you think heating it with a torch would help?

Thanks

Very well might.

You might also try taking a big c-clamp and cranking it down hard onto the lockring and try turning that...

I would also just dremel it.

Always try and try and try to take the path of least destruction first which is the penetrating oil; then take the second which would be heating it but not so hot that it burns the paint; then when all has failed then dremel it...but be very careful as to you could cut the head tube enough to weaken it, if your not sure what your doing it would be best to take it to a LBS.

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.