Originally Posted by
Scrodzilla
They're not scratches, that's just what they look like on the underside. You can't expect jewelry quality machining of a $12 cog.
It's perfectly fine.
I know not to expect too much from a cheapo part, though the 17t Miche sprocket I bought a little while ago did not have these grooves. There are lots of little scratches on it as well, though I know they won't affect the workings. Anyway, it has at least made me realise not to skimp on some things.