Widia offers Haimer Safe-lock pull-out protection for round-shanked tools

Widia explains that while shrink fit toolholders have great accuracy they lock by means of friction alone and their clamping force can be insufficient for roughing operations in these difficult to machine materials. The Weldon straight shank with a drive flat for locking in place with a clamping screw compensate for pull-out forces in roughing and other high metal removal operations but tool accuracy and run-out suffer due to characteristic offset and one line contact of the cutting tool in the holder bore. This also contributes to shorter tool life. Safe-Lock, a pull-out protection system for round-shanked cutting tools, overcomes these problems. Helical grooves are ground into the shank of the tool. These together with the respective pin drivers in the holder prevent the tool from spinning or being pulled out of the holder altogether under extreme machining conditions. Because the helical path of the Safe-Lock grooves means that the length of the tools can be adjusted, tools can be reground and pre-set as usual. Safe-Lock can be combined with shrink-fit toolholder systems and used for both high speed as well as heavy chip removal situations. The chuck is heated as usual and the tool inserted with a slightly twisting movement. The locking elements of the system find their own way into the grooves when the tool is turned into the locking position. A spring can be used to aid in the play-free positioning of the tool. The holder cools down after a few seconds, creating the press fit and positive locking. Concentric accuracy of less than 3 µm is achieved during shrinking.