EDGE RETENTION/ROLLING PART II

[KnifeGrinders]

The image does impress, it is plainly beautiful - as are your findings

[grepper]

"... but perhaps this post will slip by their notice."

Perhaps.

[EOU]

Crap-ola! We never get away with anything!

[Mark Reich]

Thanks for keeping us up to speed on this project, Mike.

The only remarkable thing I see is something other than a clean scratch pattern all the way to the EOTE.

Almost looks like a slight micro bevel, but knowing that you didn't do that, I'm surprised the blade is that sharp.

The reason you were able to sharpen before heat treat is because you didn't grind bevels on your blades.  

Normally you'd grind your bevels in the neighborhood of 3-5 dps down to an edge width of about .015", which is the thickness you would need to keep the edges from warping in HT.

Without any bevels, your blades are very thick in comparison, and you have only a very tiny apex of steel less than .015." thick, with tons of steel behind it.

This is a scale drawing of 1" wide, 1/4" thick bar stock with 15 dps bevels in the shaded portion, which is the EOU blade.

The white part is a normal flat ground blade superimposed inside the EOU blade.

Hope this makes sense.   

[grepper]

Mr. Mark, at great risk of showing my ignorance, (wouldn't be the first time ), are not the sloped sides of the EOU blade a bevel?  Why do you say, "Without any bevels, your blades are very thick in comparison" ?

Then you say, "Normally you'd grind your bevels in the neighborhood of 3-5 dps down to an edge".  Really?  I don't normally do that as far as I know.  3-5 dps?  I don't think I've ever tried to make a 3° or even a 5° bevel angle.  The blade would have to be almost flat against the belt.  I don't get it.

When I sharpen in my crude way, there is only one bevel, and only one bevel angle that extends from the edge to the side of the blade.   The width of the bevel is determined by the bevel angle.  

Sorry for being thick-headed, (I was born that way), but I don't understand.

[EOU]

Just to clarify, if clarification is needed. Here are two pictures of our #11 blade, front and back.

                                                             

Double edge, .125" thick A2 steel with 15° bevels milled (not ground) on both sides (30° inclusive) and then ground (sharpened) at approximate 15° per side with 180 grit ceramic belt until a burr was formed with subsequent attempt made to remove burr. Then heat treated. This particular sample was hardened to HRC62. Pre heat treat sharpness level 350 - 450 and post heat treat (and some additional deburring) 180/190.

[grepper]

Never mind Mr. Mark. Re-reading I get it now.

[Mike Brubacher]

Remembering back to my Interpersonal Relationship class in college I must intercede here. Your comment Grepper "Never mind Mr. Mark. Re-reading I get it now."  might seem harmless enough on the surface but might be interpreted by Mark as some failure on his part to have expressed his thoughts, initially, in a clear and concise manner. This might cause Mark great psychological angst because his self defense mechanisms might be, subconsciously, triggered. The differences in how we communicate with others are subtle as in "Do you understand what I am saying?" versus "Do you feel that I have succeeded in explaining myself fully?" See how much less threatening the latter is compared to the former?

I truly hope that Mark's zest and creative zeal have not been damaged by this exchange. Besides, I like it when Mark has to explain things to those of us less skilled in the art, I always learn something. So quit letting him off the hook Grepper. I guess I could have just said that and forget the rest of the BS.

[Bud]

Now I know why I don't have more friends. I should be more thoughtful of their feelings.  I wasn't completely sure where that was going Mike until the last few sentences and then I started laughing. I think that Mr. Mark will be just fine. i tell you, my wife watches reruns of Seinfeld and I log onto the BESS forum. Most of the time I'm laughing harder than she is. I just wonder how you guys come up with this stuff. Did you all used to play football? Without helmets?

[grepper]

Mr. Mike.  Mike, Mike, Mike.  WHAT have you been smok’n?
Or…
 
“Remembering back to my Interpersonal Relationship class in college”
Could what you have learned way, way, way back then actually still be relevant?
Or…
 
Feeeelings…. Eeeeew!
Or….

What the in the world are you talking about Mr. Mark???
Or...

 
Maybe you might be right, Mr. Mike.  That expensive education might have paid off.  In that case, here is a BIG KISS Mr. Mark, and a hug too.  I really didn’t mean it.  But rest assured, it’s not your fault for not being clear in your explanation.  I can be very slow to comprehend even the most obvious and simple things these days.  So…, it’s not you, it’s me!