Measuring blade angle

[@skiMTB]

This should have WAY more views than 18k!

[@emmanuelcavalcante3451]

Now I find a good idea! This is the kind of intelligent solution I was expecting when I googled "how to find the angle of a knife edge"! I'm gonna login with my 2 accts so I can like it twice! Good job!

[@Iamjohnsv]

Guys like you are keeping America great!

[@andyh.8074]

„How ingeniously nerdy are you?“ This guy: „YES.“

[@sciproant]

Holy shit this is genius

[@dcuttingedge5422]

This is GREAT!!! Getting some laser pointers to try it out. Thank you!!

[@wrthrash]

Genius dude, can't wait to try this out!

[@bbcc-p7w]

Awesome! Have to try it! Thank you

[@PERONOSPORAHYOSCYAMI]

Very Clever! Suggestion: Google protractor. Print out template.

[@joep5337]

Incredible. I must try this. Thanks much.

[@aarontharris]

+Joe P Cool, let me know how it works out.

[@shmookins]

This is smart. In fact, I think with some refinement, you can patent and make a product that immediately tests the sharpness of blades for any use (home, industrial use, military, science research, etc.)

[@aarontharris]

I wish. When I came up with this, I did not know it already existed but unfortunately like others have said, I'm not the first to think of this method of measuring angles.

[@allanwells4886]

Clever boy! I sharpen to 20 degrees then put a micro bevel on at 30 degrees; works for me.

[@davescarpetti]

This is brilliant. Thank you!

[@rogerhamby7551]

CATRA in the UK have been making and selling laser goniometers (as they are called) since 1978 using this principle.

[@aarontharris]

It's been mentioned :) In any case, this is a way that you can do it at home.

[@sebabalo]

Nice video. Well done

[@jojojaykay]

Pretty neat thanks for sharing

[@FajnyAleZaNiski]

+1, very smart, well done !

[@jayytee8062]

Outstanding!

[@Metalhead-4life]

Didnt know this was possible, Thanks

[@oneeyeman6258]

Freakin' Brilliant!

[@MrAbaeterno]

Brilliant. Thx for this.

[@JoshSethG]

Did you invent this technique? This is terrific!

[@aarontharris]

JoshSethG I guess I did haha, thanks!

[@mghumphrey]

Aaron Harris There is a device called a laser goniometer that uses the same idea. I like your low budget approach, but it is not a new idea.

[@aarontharris]

Matthew Humphrey good call, I certainly didn't mean to imply this is an original idea, only that I had not seen it before. now we know it's a thing ;)

[@mghumphrey]

JoshSethG Check out page 47. www.wickededgeusa.com/wp-content/uploads/2012/10/knifeshexps.pdf

[@utubeManatwork]

Very smart! Thanks.

[@vop]

So clever

[@davescarpetti]

I can't get a clean reflected line with a red laser pointer. Do you know if green is necessary?

[@aarontharris]

Wow sorry for the late reply -- I don't believe the color matters in this case. My gut tells me the fuzzier the reflected line, the less polished the surface is. You could go with the middle of the fuzzy line as a guess or you could try to polish it up a bit before measuring. Hope that helps.

[@jnbaker7422]

different color lasers have different beam shapes red is kinda fuzzy and unpredictable green is fairly predictable and circular blue is rectangular

[@AdventureSworn]

This is cool

[@crabbyhayes1076]

Brilliant

[@JohnMPavin]

Looks like a 45 degree angle to me

[@aarontharris]

@JohnMPavin its because the angle you see on the screen is compressed by the angle seen by the camera. My protector was homemade but it was accurate enough for demonstration.

[@kierstinschmidt2514]

For this method to be accurate you absolutely must move the center of the protractor to the intersection point of the bevel lines. Otherwise your angle indicator is going to be incorrect. Typically that would be the center of the protractor being at the at the same height of the knife and completely in line with the laser, and the point of reflection on the knife. Yours is lower because the table is supporting both the cardboard of the knife and the protractor sheet. It looks like you have the side to side calibration correct. If you put the angle markings on a riser you can adjust that similar to how you adjust the lateral movement of the blade.

[@aarontharris]

I think that is helpful when the laser projection is linear, not curved. When curved there is no single point on the laser projection that is "correct". The tail of the projection represents the edge of the blade. The base of the projection represents the primary bevel. The middle of the projection represents the smoothness of the transition between edge and the primary bevel (rounded in my case because I strop my knives). You're really looking for the line on the protractor that is parallel to the part of the laser projection you're interested in. As long as you are comparing the parallels, then the protractor will give you your answer without having to center anything. Sliding around to get the lines closer for comparison will likely help though.