Glossary
Back-off Angle
Relief angle back of the cutting edge of a broach tooth.
Back-of-tooth Radius
The radius on the back of the tooth in the chip space/gullet.
Broach
A cutting tool in various shapes, equipped with a series of cutting teeth.
Burnishing Button
Broach tooth without a cutting edge. A series of buttons is sometimes placed after the cutting teeth of a broach, to produce a smooth surface by material compression.
Chip breaker
Notches in the teeth of broaches which breaks up chips, facilitating their removal. On round broaches they prevent the formation of a solid ring in the chip gullet.
Chip Load
The amount of thickness, length and width / circumference of a chip. Chip Space
Space between broach teeth which accommodates chips during cut. Sometimes called the "chip gullet," it includes the face angle, face angle radius, and back-of-tooth radius.
Dwell Tooth
A tooth design that uses the finish major diameter as a pilot while cutting the minor diameter. Most often found on spline broaches where the minor diameter is held to pitch diameter.
External Broach
A broach which cuts on the external surface of the work piece.
Face Angle
Angle of the cutting edge of a broach tooth. Sometimes called the "hook" angle forms one part of the cutting edge.
Face Angle Radius
The radius just below the cutting edge that blends into the back of tooth radius.
Finishing Teeth
Teeth at the end of broach arranged at a constant size for finishing the surface.
Front Pilot
The guiding portion of a broach (usually internal) which serves as a safety check to prevent overloading of the first roughing tooth and correct axial alignment.
Gullet
Name sometimes applied to "chip space."
Gullet Depth
Height of tooth or broach gullet from root to cutting edge.
Hook Angle
Name sometimes applied to "face angle" of tooth.
Internal Broach
Broach which is pulled or pushed through a hole in the work piece to bring the hole to desired size and shape.
Land
Thickness of the top of the broach tooth.
Land, Straight
A land having no back-off angle, and used for finishing teeth to retain broach size after a series of sharpenings.
Length to First Tooth
The sum of pilot and pull shank length.
Overall Length
Total length of a broach.
Pitch
Measurement from the cutting edge of one tooth to the corresponding point on the next tooth.
Pull Broach
Broach that is pulled through or over the face of the work piece.
Pull End
That end of the broach at which it is coupled to the puller of the broaching machine.
Push Broach
A broach that is pushed through or over the surface of the work piece.
Rear Pilot
Maintains tool alignment as the final finishing teeth pass through the work piece hole. The rear pilot is slightly smaller diameter than the finishing teeth.
Rise per Tooth
Progressive increase in tooth height from tooth-to-tooth of a broach. Usually greater in roughing teeth than in semi finishing teeth. Action of step height produces the equivalent of feed in other types of machining. Twice the chip per tooth for round broaches.
Roughing Teeth
The teeth which take the first cuts in any broaching operation. Generally they take heavier cuts than the semi finishing teeth.
Semi finishing Teeth
Broach teeth, just ahead of the finishing teeth, which take the semi finishing cut.
Shear Angle
The angle between the cutting edge of a shear tooth and a line perpendicular to the broach axis or line of travel on surface broaches.
Shear Cutting Tooth
Tooth positioned at a sheer angle to the direction of broach motion. Used on surface or external broaches, and cuts with a shear action, with maximum tooth overlap.
Surface Broach
An external broach which cuts a flat or contoured surface.