Rectangle Rotary Broach Tool
The basic set-up for hex and square rotary broaching applications applies to rectangle forms as well. A chamfer is required at the opening of the hole, all the way out to the sharp corners of the forms. The chamfer is important for getting the chips to begin to curl properly.
Oversize pilot holes are also important for rotary broaching. The oversize pilot hole separates the chips, reduces the chip size and pressure required for rotary broaching. The oversize pilot hole will leave a small radius in the longest flat of the rectangle.
Finally, there must be room in the bottom of the hole for chip accumulation. Clearance for chips may not be necessary for through holes, but blind holes will require deeper pilot hole or an undercut. Chips can be removed after broaching with a drill or end mill.
Although most rectangles require sharp corners, that is not the case in every application. The sharp corners can be ground (in the form of a spun ground diameter), to improve tool life and reduce chip size, chip clearance and thrust requirements.
With rectangles, there can also be a need to align the broach and rectangle form to another feature of the part. This is not a normal requirement in the majority of rotary broaching applications. Therefore, the rotary broach tool holder does not have a built in alignment feature.
There are a number of ways alignment of the rectangle broach can be accomplished. The first is manually, although this method is not ideal in production settings. The methods suitable for production include the use of a rotary broach brake, guide post or guide bar.
Rectangle broaches can also be used in pecking or punching operations to form rectangles, hexagons and other forms. The broach is held in a fixed tool holder instead of a rotary broach holder, and is pecked or punched into the part in small increments until full depth in achieved. Advantages of this method include the ability to remove the broach and drill out the chips periodically, and the ability to shape or cut hard materials that cannot be formed by rotary broaching.
To get a quote on a rectangle broach, please provide the length, width and depth of the hole. Also, the part material, drawing, and quantity are also helpful. Rectangle broaches are custom tools and normally require about five days for delivery.
To request a quote on a Rectangle Rotary Broach fill out our online quote form or call us at 239-628-4800.