In article 2,
DerbyBorn writes:
I have never seen one with a slotted screw. Are you sure it isn't a broken
off shaft that lookes like a screw slot?

I don't think I've seen one on a radiator, but it looks the same
idea as a gas restrictor valve, commonly used to supply a gas fire
in a fireplace.

Most "lockshield" valves are ordinary valves but with a cap rather than a
knob.

--
Andrew Gabriel
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