As of the last time I checked, if a guild is aligned, building a drill in an OP that is of the opposite alignment is useless. You don't get anything out of it. Neutral guilds can use both, however.
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Remembering Tyneetryk
Phaedreas Tears - 15 years old and first(*) of true neutral guilds in Atys.
(*) This statement is contested, but we are certainly the longest lasting.
<clowns | me & you | jokers>