Nice title for this thread.
Not sure where you got a D3100 with a M10 thread. We have never made D3100 with a M10. Back in 06 we made some with M8 thread, but never M10. The 580 come with M6, because that is what every D3100 since 06 uses.
If you really meant M8, then you can give us a call and we have the posts that work with it.