Blind & Spiral Broaching
Blind broaching refers to the machining of a piece part in which the broaching tool is unable to, because of the design of the part, pass completely through or completely past the part. The broach therefore must cut into a ‘blind’ cavity of some sort. Designing the tooling for, and executing the process of blind broaching is very much an art that is reserved for the most experienced of craftsmen. V W Broaching Service is pleased to perform all types of blind broaching operations, from the most simple ‘punching’ of a shape into a round hole, to more complex forms involving multiple passes using several tools. An example of a blind broaching operation would be the cutting of an internal hexagon into a headless setscrew.
Spiral broaching, sometimes referred to as helical broaching, or continuous engagement broaching, is used when a spiral spline or other form is desired either in the internal of a piece part or the external. This is perhaps the most complex form of broaching, and requires special tool making and production equipment, not commonly found in machine shops, even if they have a broaching department. The spiral form can be accomplished in several different ways; but in all cases either the piece part or the broaching tool is allowed to rotate as the broaching tool passes through the piece part. In the case of an external spiral form, the pot broach most often is held in place while the piece part is rotated and pushed over the broaching tool. Examples of spiral broaching applications are: gun rifling and spiral transmission gears.