8-32 is an imperial size, and doesn't have a direct UK/Metric equivalent as far as i know, i ordered some 8-32 screws off of eBay to replace the one that came with my ascend. A quick google tells me that an imperial 8-32 converts to a M4 0.7, but i have been told that this is approximate and that ideally you risk damaging the threading if you mix-and-match.