8 mm scandi bevel on a 4 mm blank

[awestib]

Hi everybody and merry christmas!
I need some help figuring out what angle approximately would be an 8 mm scandi bevel on a 4 mm thick blank? In other words, if I want a 12.5 degree scandi bevel on 4 mm, how wide would the bevel be? Thanks everybody for help!

 

[carbonsteel928]

I wrote this a while ago to calculate angles... hit the link and plug in your numbers. You'll have to convert over to imperial though. Hope this helps.

https://docs.google.com/spreadsheet/ccc?key=0AhJg7rJKBKEvdGNMcTRtTGdtTmdtMXNCVmVGYmRaWkE#gid=0

 

[Hesparus]

To calculate the edge angle of a scandi grind, take the reverse sine of one half the blade thickness divided by the width of the bevel. This gives you the angle of one side, so you'll have to multiply it by two to get the inclusive angle. When I learned trigonometry in high school, I was sure I would never use it...
If my calculations are correct: For your 8mm bevel, I get 14.5º per side for a total angle of 29º. You'd need a 9.24mm bevel (with no secondary bevel) on each side to hit 25º exactly.

- Chris

 

[awestib]

Thanks so much guys, I appreciate it!