Yes, they actually work! Not just the cutting blade, but the blade replacement triggers as well.
It's not until you see the progress and interior shots that you realise how much work went into these things.
If you want one of your own - and wherever you live would actually let this get sent through the mail - creator TKTK is taking orders.
フルメタル立体機動装置 完成（動画あり）[Joshualawn, via neatorama]