Good question. You can use a BIG-PLUS tool holder on a machine that doesn't have a BIG-PLUS spindle. It will work like any other standard tool holder, but you won't get the added rigidity and benefits that a BIG-PLUS connection offers. Charlie from Andretti Autosport does a good job of demonstrating this here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-VU7D-nGULD8.htmlsi=XC9rj2B6DgX5dmqZ
