Yes it's quite a simple little semi atomatic device thats been around for a few years, But you need a bandsaw.. You just push it back and forth by hand.I was going to make it fully automatic with a windscreen wiper motor..a bit like this one..but I've not got round to it yet. http://www.youtube.com/watch?v=h-pdUWoNjPo
Here's Mrs Timbuck helping me out.