Forstner bits are slow, but not like that. It sounds like you got some
super-low quality bits. Did you try other sizes elsewhere to see how
they worked? That said, I don't understand why you're trying to use a
bit designed to cut a super clean edged flat bottomed hole in a home
construction situation. A twist bit should make a clean enough hole
here. I'd take those Forstner bits back.

plus smaller ones like the 3/8 can plug up pretty easily and not drill
well.
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