VDI ToolHolders consist of a serrated shaft that is inserted into an opening on the face of the turret. The toolholder is locked in place by a mating part with teeth located inside the turret… when an Allen wrench is used to tighten the locking screw, situated on the turret face, the mechanism activates and holds the toolholder firmly in position. The rotation of the toolholder is prevented by a pin located on the mounting surface of the turret. Unlike BMT toolholders, VDI toolholders can be mounted either on the outer circumference of the turret or on its face, depending on the turret configuration of the machine in use.

The BMT, or “Base Mounted Turret”, is a popular choice when seeking a more rigid configuration. The BMT holder is securely fastened to the face of the turret with 4 socket head cap screws, and is positioned and further secured with locating keys present on the turret face. Thanks to these keys, it is not necessary to indicate the toolholder to straighten it, which is often required with VDI toolholders. Additionally, the simple design of the BMT holder’s mounting configuration makes it an excellent choice for creating custom holders for special circumstances – something that would be very difficult with VDI toolholders.