The thread pitch is going to be a bit off even if the diameter is close, but as skellyo said, imperial sizes are numbers below 1/4". If screwing into plastic, it won't much matter, but aluminum/steel pieces may get the threads chewed out. If we knew what is what for, we could probably help you out.
It is actually the small 4 screws holding the end on of the Neu Motors. I took the screw into a fasterner shop and they said 2.5 x 3 but couldn't get any screws that small. I asked Steve Neu how big the screws were and he said 0-80 (sorry I typed 0.80 in 1st post) They do exist - http://www.microfasteners.com.au/fas...ketScrews.html
I just realised that the screws that hold the shock pinion on the shaft is 2-56 x 1/4" and the screw looked about that size so I thought I would try it on the motor and it fit but you could wobble the screw a tiny bit in the hole. But isn't 2-56 bigger than 0-80?