Straddle & Pot Broaching
Straddle broaching refers to cutting more than one surface of a piece part in one stroke, by using multiple broach tools which span or straddle the part. It is most often employed in smaller parts requiring mirror cuts or equal cuts to be made on a single part. Broaching tools, mounted in holders, and affixed to the ram of a vertical or high-speed broaching machine, can be used to cut virtually any surface of a part in the same plane, and is limited only by the ability to hold the part firmly enough to withstand the broaching process. An example of a straddle broaching application would be forming a square external shape on the end of a cylindrical valve stem. The first two surfaces are cut, the part is then indexed at 90 degrees and the final two surfaces are cut. Straddle broaching is typically fast, while still being able to hold very close tolerances.
Pot broaching refers to the process of cutting the entire outside diameter of a piece part, using multiple broaches which are held in a broach holder or ‘pot’. The pot is a housing with a hole in the center that is designed to hold many broaching tools, usually concentrically, throughout its entire inside diameter. The pot is then pushed over the piece part to be cut, or conversely, the piece part is pushed through the pot broaching tool. An example of a pot broaching operation would be the cutting of external splines on a gear. Typical broaching companies do not routinely undertake pot broaching, because of the complexity of the tooling and fixtures involved. V W Broaching is proud to continue to design and build pot broaching tools, either for use in our production machines, or those of our customer.