Auto share on FaceBook & Twitter: Need Help

Hi gurus,
need a little help.

I have a tech-forum and I want all newly created threads to autoshare on facebook & Twitter. Is there any free way to do that?

I was thinking to go with dlvr.it but it pulls contents as soon as the feed is updated. So it will pull contents as soon as a new reply is posted. I just want the new threads to be shared.