Drainage holes or not?

So I have finally got around to starting sanding away at an old bike I picked up for a project. Been very lucky a small ding in the top tube(which is step thru so won't notice as much and I can camo over with a protector or something) and that's it really.

Anyways, it doesn't have any drainage holes but from what I can see it doesn't have much/any rust either. Even the chipped away paint parts had little rust once I got the mud and crud off. Would it be worth drilling holes or could the cause more bad than good?

The plan for the bike is that after a respray and modern brakes+cranks it will make a nice bike for my partner to just pop to the shops and things on until she feels more confident and wants a better bike. It won't be left out in the elements and I doubt she will ride in the elements either.

Single drainage hole at the bottom of the bottom bracket. Waters going to get in somehow, so you may as well give it a place to escape.

Most steel seat stays tend to have drain holes as well...as long as there is a little oil or grease in there, it'll just stop being a water trap!

Red

Big dredge on this, but do people think drilling a hole where there isn't one is a good idea? I just took the bottom bracket out from a frame I recently bought and found quite a lot of rust+ water inside. Seems structurally okay otherwise - is it worth drilling a hole?

I reckon so to let the inevitable water out again. I am neither an engineer, bike mechanic or materials scientist but I've done it with a c.2/3 mm hole and I'm still here riding the same bikes.

Drill it. Frame builders aren't doing any wizardry when putting drainage holes in, they're just drilling it so go ahead. It's always a good idea to have one in the BB on a steel frame