There should be scalp plate on the strike side of the door.
Remove the scalp plate, usually held with 2 very short screws- be
careful they are hard to come by and they are very short.

you should now see a set screw that lines up with the cylinder.
Back this screw out a few turns and screw your cylinder out.
Notice on your new cylinder that there is a groove cut in the side
through the threads. This groove is what the screw grabs.
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______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




"Anthona" wrote in message
oups.com...
I lost my last key for the entrance door. I have another cylinder
that
i would like to replace it with. I took off the 4 screws and
then
inserted a screw driver into the key slot and tried to turn the
cylinder into the opposite direction, but it would not budge. On
the
inside there is the latch that locks the door from the inside
with a
bolt...looks like its attached to that cylinder. If the last
resort is
to get a locksmith to make keys from this lock, is it worth it
or
should I just get it repaired? The cost, if known? Thanks