As the others have said DO NOT use WD40 as a lubricant,I would only use it on rusty bolts to free them up even then there's alot better lube to use than WD.I think the confusion comes from the can it's self,as they write lubricates ,penetrates,protects on the side.
We have the sewing machine oil in 2-grades standard stainless(clear) & a heavier oil that isn't clear for heavy Industrial machines.And that's what we recommend to use.
Bob