Sounds like the crank arm is loose. Just grease them up (BB spindle/axle and crank arm plus the cotter slot) and then install the cotter pin. The grease will allow the cotter pin to fit more tightly (no matter what tool/method is used for install) as well as make future removals easier. Should be quiet after that. The cotter pins on each side should be installed opposite of each other...ie not on the same side.

What grade of bearings did you use in the BB? Might have gotten a bad batch too.

Sometimes I want to buy a square taper spindle/axle or go cartridge and upgrade the cranks. But I kind of like the look of cottered cranks and it's never really gave me any big headaches. Suppose when the chainring finally wears out, I'll make the change then.