I've noticed (no big surprise) that store bought dowels are slightly undersized. For example some 3/8" dowels I got from Woodcraft have a noticable slop when inserting them into a 3/8" hole. I've tried several 3/8" bits. Measured with calipers, the dowels are slightly undersized. I would not be too worried about it but there is enough gap to be noticable after glue up on some scrap.
Do you guys make your own dowels? Any particular recommedations for the dowel cutter?