Bevel Angles

[Claude]

I'm sure you've all heard that the "best" angle to sharpen your chisels/gouges is 18 degrees, or 20 degrees, or 24 degrees, or whatever...so how do you know how much say, 20 degrees, is - what does a 20 degree angle look like. Below are two tables, one standard inches, the other metric, that show you how to accurately draw a given angle.

Take a piece of paper, card stock, cardboard back from a pad of paper. Draw a three inch long (75mm) horizontal line on it. Then, at the right hand end (or left end, if you're left handed) draw a vertical line as long as the table shows for the angle you want. Example: You draw a 3 inch long horizontal line. Since you want a 20 degree angle, you draw a vertical line exactly 1 1/16 (17/16ths) long at one end of the horizontal line. Connect the two ends and the angle, as shown in the drawing, will be exactly 20 degrees). Cut out the triangle. Go over to your bench and press the bevel of your chisel flat to the bench so the handle sticks up in the air. Slide the little paper triangle under the chisel and see if it is greater than 20 degrees or less than 20 degrees.

You could also go to your sharpening stone, put the cardboard triangle on the stone, and then set your chisel on top of it to get the right angle for sharpening...

Hope this helps you. Trying to do this with trigonometry, cosines, and arctangents can be very confusing, but anyone can draw a triangle.

Claude

[SeaLeveler]

Thanks for the info.Tony

[Bandaid]

Thanks Claude, a very usefull tip.

[Stryder7]

Very very helpful...that had always kind of confused me... now it's easy
Marianne

[squbrigg]

I'm lazy, I bought the little brass angle jig for blades from Lee Valley Tools, and in a glance I have the angle I need.

Bob

[Eddy-Smiles]

Great chart Claude! Don't know how I missed before!

[Tom Ellis]

Thanks Claude, a great visual reference.
Tom

[Marci MN]

Claude, thank you for linking to this post. I will make this 'jig' but still have a question. Is this jig for 20* for the long angle or the short one that does the cutting or the 'white line' angle? Theres two angles on each side of the blade right?

Marcia.

[Claude]

Originally Posted by Marci MN

Claude, thank you for linking to this post. I will make this 'jig' but still have a question. Is this jig for 20* for the long angle or the short one that does the cutting or the 'white line' angle? Theres two angles on each side of the blade right?

Marcia.

Depends... If you are sharpening a chisel which only has one side beveled, and you want a 20° bevel on it, then you'd make a 20° angle piece of card stock. For a knife blade, which is beveled on both sides, you'd make a 10° angle piece of card stock - 10° on each side will give you a 20° total for the blade.

[Marci MN]

Ok... I need to make a 10* (where do you find that tiny degree symbol on keyboard) jig for knife sharpening. I'll be honest.. i'm reallly lost on this. LOL I'm hoping once I make the jig it will make sense.

M.