This model is inspired the Black Tiger butterfly knife (balisong) from Counter-Strike: Global Offensive.
This model is comically oversized - because bigger is better, right? It was designed so that the blade and handles are as large as possible to be printed on a 220 x 220 print bed. 50% scale is about normal size for normal sized hands.
Handles are fastened to the blade with one M5 x 25 countersunk bolt each.