Ah.. scratchiness is a broad term for friction.. which is NOT a qualitative measure or a subjective measure..
Friction can be measured and I agree it is an objective measure. However scratchiness is subjective. It is just like term heavy. Weight can be measured and it is objective, but heavy is subjective term. Some feel black switches are just fine for them, some say they are heavy(or stiff). It all depends on what your reference point is. If one is used to Model M, then he/she will be just fine with blacks.
They do NOT lube cherry stems. Because if the lube got in between the metal / metal contact, the button would chatter. They only lube the joint area at the bottom. where the plate contacts the housing.
I don't know what you mean by joint area. But Cherry stems are lubricated on the surface where it meets metal bump since the place is lubricated with some sort of grease.
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Source: You can also see the slight dabs of clear grease on either side. If you clean the switch with solvents you may find the switch to be grainier as a result. http://geekhack.org/showwiki.php?title=Cherry+switches+and+boards
Here is a photo of relatively new Topre slider. You can see thin coat of lube.
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You can further compare it with an old Topre slider. The lube is not there anymore and it is scratched.
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