Convex Edge snafu

Devilnut

Devilnut

Joined
Aug 4, 2003
Messages
246
I put a convex edge on my Steel Heart with mouse pad/ sand paper and proceeded to bash the crap out of it. Now, the more I sharpen it, the less sharp it feels. I wonder if any of you guys that have knives with convex edges have run in to this problem. I think that perhaps I am rounding the edge out? The knife just doesn't feel sharp at all, it feels thick. I appreciate any suggestions.
 
Devilnut said:
I put a convex edge on my Steel Heart with mouse pad/ sand paper and proceeded to bash the crap out of it. Now, the more I sharpen it, the less sharp it feels. I wonder if any of you guys that have knives with convex edges have run in to this problem. I think that perhaps I am rounding the edge out? The knife just doesn't feel sharp at all, it feels thick. I appreciate any suggestions.
Click to expand...

There is the possibility of "raking" the edge, and not even being aware of it - or even think it's not possible.......

here's something I wrote elsewhere:

I used to find using crock-sticks for a final touch up improved some blades AFTER stropping -
- that is I used to,
until I figured that it probably was my stropping technique that may have been spoiling the fine edge.

I still can't say what exactly I was doing wrong - afterall it should be real easy to strop a blade - shouldn't it?

The only consistent thing that may have contributed to fewer blades needing any further touch-ups after a strop was a change in how I turned the blade over.

Sounds stupid and simple that I found it hard to believe it may have made any difference.

Instead of just flipping the blade over to strop the other side, I had to deliberately re-learn how to turn the blade over by lifting the edge first and turn the blade over pivoting over the spine - I have been told that this action avoids the possibility of raking the blade edge.

Since I was very aware many of my blades seemed need a touch-up using crock-sticks after stropping - and once I admitted to myself that I might doing something wrong - I had been careful not to rake the blade edge - always carefully lifting the edge off the strop at the end of the stropping stroke.

But even that did not improve things - but once I started to flip over the blade in the manner/direction described - I cannot swear everything got better all of a sudden - but over time it seemed that fewer and fewer of my blades need a final crock-stick touch up....

Maybe, I've just become less fussy - but I don't think so - I think that flipping the blade over correctly probably has saved the blade's edge from being raked - although I still can't figure how I was raking the edges before......

go figure.

--
Vincent

http://UnknownVincent.cjb.Net
http://UnknownVT.cjb.Net
 
It sounds like you are getting in a hurry and using too much pressure on your mouse pad. If you use too much pressure or your pad is too soft you will round off your edge. Also you need to finish with an extremely fine grit if you want a fine edge. If you have gotten your profile in really bad shape you might need to work on something like a stiff leather backing or even a hard flat surface to recover acuteness at the edge before you finish stropping on something a little softer.
 
Devilnut,
you may want to contact Daniel Koster,
he is the captain of the convex edge brigade.
good luck.
 
The first thing to check is actual edge-formation: Do the edge-tapers of each side actually meet at the final edge? Did you check for burr-formation in forming the initial edge?

If you did, then the problem is almost certainly due to either/or:
- too high blade-to-hone angle.
- too much pressure on the elastic backing.
- combination of both.

Trailing the edge across an elastic hone (mousepad or strop) creates a 'wave' as the surface deforms and reforms. The final edge bevel is formed at the rear face of this wave. The effective resultant bevel angle for each side of the bevel is always greater than the blade-to-hone angle.

The final taper at each side of the edge can easily exceed 5 degrees greater than the intended angle (easily exceeding 10 degrees in excess of the intended final included angle) depending on applied pressure on the elastic hone. Add pressure and the +10 degrees easily becomes +20 degrees or more.

Hope this helps!
 
You must log in or register to reply here.
Back
Top