Originally Posted by dsbrantjr

Keep in mind that an ordinary cutting tap will only remove material so might leave the hole oversized. If you could obtain a thread-forming tap like this one: 3mm x 5 Metric HSS Thread Forming Tap M3 x 0 5mm Pitch | eBay
or use a well-oiled non-stainless screw as a chaser (stainless tends to gall) you might have better success.