Normally, as is from the factory - go ahead and lace, lube and true.
However, sometimes when rebuilding a wheel that was originally machine built - you'll find an eyelet that a nipple ate into creating a burr...
Smoothing / removing the burr would certainly help - long as there's 2mm or more of material left (alloy rim) everything should be fine.
Generally it is okay to drill presta to schraeder...clean the burrs with a fine
file when you are done - minor filing is usually enough. Examine the rim before you drill - judgement call really on your part.
If anyone does insist on fine sanding or polishing rim eyelet seats to a fine or mirror finish, I have to ask: What are you trying to achieve?
I.e., after decades of rims getting built as-is and serving out useful lives before being let out to pasture - what sudden societal revolutionary design paragdigm shift has occurred that requires it?
Robert Shackelford San Jose, CA USA
Quoting John Hurley <JHurley@jdabrams.com>:
> Have any of you found a need or value in preparing/cleaning/deburring
> the rim eyelets on the inside, so the spoke nipples will seat well? How
> about deburring and smoothing the valve stem hole? Is there any harm in
> reaming the valve stem hole from Presta size to Shraeder size?
> John Hurley
> Austin, Texas, USA