Triangle Shank
The triangle shank is almost always made by machining three flats on round bar stock. It is intended as a minor modification of a straight shank, still allowing it to be held in a 3-jaw drill chuck, but allowing higher torque transmission and limited slipping.
- Can be held in a drill chuck
- High torque transmission
- Moderately accurate centering
- Cannot be held in a collet
Read more about this topic: Drill Bit Shank