Tom_G

Ahh, so your method seems pretty quick as a way to get a near optimally uniform sharpening angle, since, as you point out that angle is uniform if the edge of the knife traces out part of a circle about the pivot point -and- that the sharpening angle is uniform along a flat edge even if its tilted.  I came across a discussion, in my…[Read more]

Got it — thanks and understood.  I am just a newbie with a computational/design bent for whom you have correctly identified a big part of my justification for doing this — its fun!

Marc,

Thanks for digging up the info!  The features of that curve is part of the calculation above.  I am pretty sure the graph is of the formula Offset = Height * atan(a fixed angle) + (1/2 of the width of the diamond block).   It incorporates the width of the block as part of the analysis to gives you how far off the center the ball sho…[Read more]

So I have some preliminary results.  These are for the following (inexpensive) knife.

I have calculated the real sharpening angle for the various positions across that blade for a number of different mounting spots.  The mounting spots are 2″, 2.25″ 2.5″ ….. up to 4″ from the blade start (right side of the image).  The sharpening angle is ad…[Read more]

Nope its just a trial posting.  The image is of a cell phone picture of a knife that has been subjected to an edge finding program  as a first step toward converting it into x,y numbers for analysis.   Those letters you see are  whats printed on the red folder I used as a background,  The edge find does pretty well with those.

Thanks again for t…[Read more]

Success — but I have to add it as an attachment, then post, then insert as media in a new post, then delete original post with the attachment.

Not sure this is how its supposed to work, but thanks for the help!!!

Marc H,

Thanks for answering.  But the issue is that I am never offered that second step. (i.e. click it so it’s marked with a check mark in the square”) I can try to add my image to the image gallery, but it fails and tells me: “Sorry, you are not allowed to attach files to this post.”  Since it never makes it tot he gallery, I cannot insert it…[Read more]

airscapes — thanks for touching base, and for the info and guidance about sharpening angles.    I am thinking that I did not introduce  that first post very well.  Rather than determining an angle to use for a blade, the calculation is aimed at finding the variation of the sharpening angle for each portion of the blade.  My understanding is that…[Read more]