Radial Rake Angle and Radial Relief Angle Measurement on the Cutting Plane
The method for measuring angles on the tool cutting plane scan is illustrated below:

Radial Rake Angle (α)
- Sweep along the tool rotation direction to find the trailing point A of the cutting edge
- Connect point A to the center O
- The angle ∠OAA' between line OA and the first polyline endpoint A' on the cutting side of the edge is the rake angle α
Radial Relief Angle (β)
- Find the contact point B between the tool and the envelope circle
- Construct the tangent line Lt to the envelope circle at point B
- BB' is the first line segment on the relief side of the tool
- Pick an arbitrary point B'' on Lt in the relief direction
- The angle ∠B'BB'' between BB' and Lt is the relief angle β