Not drill the hole crooked, being that if you do drill it out crooked, the rim is pretty much ruined, after that, if it's drilled out, you have to go in with a small round file to smoothen out the burrs, if you don't, you will get flat after flat, after flat.
Schrader is an outdated design that may work good for car purposes, but should go the way of the woods valve in regards to bicycle tubes.
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Appreciate the old bikes more than the new.