When using a CNC lathe for milling, there are two options for installing live tool holders: VDI (Verein Deutscher Ingenieure) or BMT (Base Clamp Tool).
VDI is considered to be the most widely used tower in the world as it has been released for over 20 years. The tool is held in place by a mating tooth portion that is positioned inside the tower. Then the locking screw located on the head of the head is tightened with an Allen key, the mechanism exerts a clamping pressure that holds the tool securely in place. Before turning the handle, a pin is secured on the mounting surface of the tower.
The VDI tool holder must show straightness during assembly, by turning the screw to check the accuracy, you can adjust the straightness to any need.
BMT is the latest technology for a milling machine and is a stiffer solution. When attaching the tool holder to the head, the operator uses 4 bolts to tighten the tool holder, which is located and additionally secured with set wrenches on the head face. These wrenches eliminate the need to point to the toolholder to straighten it… which is most often necessary on VDI toolholders.
The operator does not need to adjust the straightness of the BMT tool holder, the overall precision is based on the precision of the tool holder and cannot be adjusted.
● Only one screw to tighten the handle, it is easy to install and faster for the operator.
● Lower upfront investment, the cost of the tool holder is cheaper than the BMT tool holder.
● The operator can adjust the straightness and precision of the handle.
● Stiffer, used for heavy cutting.
● The accuracy of the straight line is constant, the operator does not need to adjust the straightness.
Regardless of the machine builder, there are basically two popular methods of attaching toolholders to your mill / lathe… BMT or VDI. Some builders even offer machines with both turret configurations as an option - however, they usually standardize on one or the other depending on the specific market or region of sale.
BMT, or "base-mounted turret," is often considered a more rigid configuration. The BMT mount attaches securely to the turret face with 4 socket-head bolts and is positioned and additionally secured with retaining wrenches on the turret face. These wrenches eliminate the need to point to the tool holder to straighten it, which is most often necessary with VDI tool holders. In addition, the simple design of the BMT mount's mounting configuration makes it a good candidate for DIY (do-it-yourself) mounts for special occasions - something that would be very difficult with a VDI.
VDI (or "Verein Deutscher Ingenieure", which roughly means the Association of German Engineers) holders have a serrated shaft that is inserted into a hole in the turret face. The tool is held in place by a mating tooth portion that is positioned inside the turret ... when an Allen key is used to tighten the locking bolt on the face of the turret, the mechanism applies a clamping pressure to hold the tool securely in place. Before turning the handle, a pin is secured on the mounting surface of the tower.
Unlike BMT turrets, VDI toolholders can be mounted on any outer circumference of the turret, or on the face of the turret, depending on the turret configuration of the machine in question.
IMTS Exhibition includes manufacturers from around the world. Send us a message with your requirements and our IMTS Experts will happily help you with your questions.