A few years ago I brought a usb microscope from Maplin. The only drawback was that it was handheld and did not come with a stand. I have dug it out and found that it works with the Camera app in windows 8 so I decided to make a mount for it to attach to a flexi magnifying glass stand that I had. The mount hole is 9.3mm so can be threaded for M10. It screwed straight onto my stand without needing to thread it.

Made a quick update. Made the clips slightly longer just to get a better hold on the cam.

Added a cable clip to keep the usb cable tidy.