Rafter, framing & T-bevel are useful types of this "geometric" tool
This portion of the User Guide will be particularly useful if you are new to... [DOC] [TLE] Knife Angle chart - Every type of knife blade has its own bevel angle ... [PAR] A camping knife or pocket knife should have a bevel of 10 to 15 degrees; its edge 
is less keen but will ... See more about Sharpening Tools, Charts and Knives.