Calculating the Angle of the Bevel
To calculate the angle of the bevel we need to do some trigonometry - Yes, we are actually going to need to use math. To calculate this angle you first need 2 measurements -
- The height that you would like the bevel and
- How deep you are going to cut the bevel into the knife - see image above.*Important, you need to leave about 1mm(3/64ths) not removed from the blade of the knife (Don't worry, you will grind that sharp later as your Primary bevel/cutting edge).
- Now, Divide the depth of the bevel by the height of the bevel. Don't worry, you will end up with something like 0.0876.
- Go to this website and enter the number that you calculated into the Inverse Tangent Calculator, and click Calculate.
- Make note of the number of Degrees that it is calculated as. 0.087 came out as 5.0063 degrees - so I will just round to the nearest 1 decimal. e.g. 5.0 degrees.
- Set up the Blade grinding JIG to 90 degrees PLUS the angle that you calculated. E.g. 90 + 5 = 95 degrees.
- Go ahead and grind the bevel - make sure that your teacher has checked your calculations, how you rigged the blade in the JIG and how you should now grind the bevel.