Blade angle measures

[BJE]

What would be an accurate, innexpensive, and simple way to measure what my blade angles are?

 

[Bill DeShivs]

A protractor?
Bill

 

[gud4u]

For best accuracy, an accurate caliper and a scientific calculator with trig functions.

The protractor is cheap and accuracy depends on your visual comparison of angles. That comparison accuracy may be enhanced a bit by projecting the shadow of the blade against the angle scale of the protractor.

Hope this helps!

 

[Cliff Stamp]

It would be difficult to estimate edge angles off a protractor because you would basically have to extent the angles, this can be done, but it tends to be highly in accurate unless you split them with a laser, which is how angle measuring devices actually work. Angles can be measured directly with a caliper on the bevel itself or you can measure the height of the blade off of the stone and calculate the angle. Both of these are high school trig problems.

-Cliff

 

[Dog of War]

Agree with gud4u, a caliper is a great tool for any blade enthusiast .... even look cool in knife photos IMO --

If you don't have one, they're good for everything from identifying all kinds of blade dimensions, size/pitch of screws, measuring depth and inside circumferences, etc., and lots of uses throughout the workshop/garage/home.

BTW spreadsheet software will do trig functions you need for edge angles too.

 

[hardheart]

I've got a cheap dial caliper. Seems to work ok, checked it against some feeler gauges and the measurements match.
and there's trig calculators online, here's one, google will net you plenty
http://www.carbidedepot.com/formulas-trigright.asp

 

[matt321]

Here is a thread at kf on this subject.

http://knifeforums.com/forums/showtopic.php?tid/778217/

an excerpt...
"Want a 20 degree angle? Divide your blade width (at the heel) by 3. Want 15 degrees? Divide by 4. Divide by 5 for a 12 degree angle and 6 for a 10 degree angle.

10 degree = 6
12 degree = 5
15 degree = 4
20 degree = 3

Ding! Instant Magic Angle Finder"

 

[HoB]

To measure what the actual angle directly at the edge is, I like to push an edge along the edge of a piece of paper, increasing the angle till it bites. I then take a ruler along the blade and draw a line on the piece of paper. The angle can then be measured on the piece of paper. In case of a full flat grind, the blade bevel you still have to add, but that you can easily measure with the caliper method.