First Rat! edge profiling ???

J

JWBirch

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Oct 13, 2002
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1,167
Hello all, some of you might be familiar with me from the Busse forum, but I'm now an official swamp dweller with the purchase of a Desert Jack. WOOHOO!!!

It's just what I wanted, and I got it for a fair price to boot. My only worry is that the edge has been re-profiled to a zero-edge, and has worrisome tiny chunks of actual edge missing. It was reprofiled on mousepad/sandpaper with a final grit of 600, but (and I am not making accusations here, only trying to create a visual picture) it looks exactly like a blade that's been sharpened on a Kitchen V grinder: the final grind lines are horizontal rather than vertical, with missing parts of the edge about .1mmdeep by .25mmlong, by my calibrated eye and 10x loupe.

The "serrations" do make it a wicked slicer!! but I'm worried the edge won't be as durable as I need it to be.
I'd like to keep it, but I need some advice on how to get the edge into a more durable and uniform state.

Thanks Rats!
JB
 
The reprofiling could easily have been done on a mousepad with paper and have horizontal lines. I have never achieved satisfactory (to me) results stropping on paper in the traditional way, I always move the edge lengthwise across the paper as I find it much easier to maintain a consistent angle. Sounds like this may have got too thin, though, or that it was sharpened down to a wire edge which fractured later on.

If you want to reprofile it, it is quite easy--just hold the edge at a higher angle when stropping (or grinding on a stone if you wish to turn it into a V-grind) and it will begin cutting a new edge bevel. You'll have evidence of the old one above it, but that won't hurt anything, and will eventually disappear with more sharpening.

Or, you could try working on the existing edge--if there are actual chips missing I would go to 320 grit, or so, to speed things up. Use the same angle that it has been sharpened at already, and when you have it down to a smooth and consitent edge with the 320, you can go as fine as you want. Most of my slicers don't get much higher than 600-800, but I usually take chopping blades to 2000 or even higher, for durability. Still, there's no reason a 600 grit edge should be fragile, so I would say the knife hit something pretty hard, or there was a mistake during the reprofiling. Either way, it's easily correctible, it'll just take a little time.

Just go slow, keep you angles as consistent as you can, and don't move to a new grit until the one you're currently working on has produced a uniform effect along the entire edge.
 
Roger that, looks like I'll make an evening of it. Hopefully she'll clean up well enough.

Thanks for the advice.
JB
 
I'm no steel guru... unlike t1mpani:D . But do you think since the edge is chipping in places that the heat treat could have been damaged by the previous owner taking shortcuts (ie, dremel or grinding wheel) to try and achieve their goal.

No "slam" intended; I don't know identity of the previous owner of the DJ. If they read this, please know that there is no maliscious intent in this post.

I just know that when I was slightly younger and considerably more naive, I ruined the heat treat on a, admittedly, cheap blade by doing the high-speed cheat. The edge became very brittle and chipped easily.
 
That's my main concern. I've touched it up a bit with a falkniven DC4, and have a ways to go before I feel confident: but the diamond isn't cutting like it would on poorly treated steel so that at least builds confidence. This afternoon sometime I'm going to hit up some treated 2x4 with it to see if it can maintain an edge like something I'm used to, or if it rolls, chips and deforms. I think it'll be ok though.
Thanks for the replies,
JB
 
JWBirch said:
It was reprofiled on mousepad/sandpaper with a final grit of 600, but (and I am not making accusations here, only trying to create a visual picture) it looks exactly like a blade that's been sharpened on a Kitchen V grinder: the final grind lines are horizontal rather than vertical, with missing parts of the edge about .1mmdeep by .25mmlong, by my calibrated eye and 10x loupe.
Click to expand...

That is about what I would expect given that sharpening, never run the abrasive along the edge, it increases friction significantly, and weakens the edge dramatically.

-Cliff
 
Edge Pro runs the abrasive vertically. After the DC4 got my DesJak to "field acceptable" I decided to finish up on my edge pro, just for peace of mind. It is now in "good" condition and ready for testing later.

I've heard nothing but bad things about kitchen sharpeners being used on field knives (and kitchen knives for that matter). But they are EZ, right? so they get used a lot, and "a lot" gets confused with "acceptable", and there you go... I admit that I use a kitchen V grinder, (handheld with the ceramic wheels, not electric) to touch up kitchen blades that are still a bit dull after steeling but not dull enough to go to the EdgePro. It's a compromise, and only on knives that I"m willing to compromise on. My wustoff set came with very specific instructions that electric kitchen grinders are not only the fastest way to destroy a knife, but the quickest way to void their warranty as well.

These are my opinions and experiences, ymmv, and I'm open to other opinions and experiences...
JB
 
The Edge Pro runs 90 to the edge, most of the pull throughs will grate 180 degrees along it yes. They are good for quick touchups on lower end knives. You sharpen them frequently at obtuse angles. On higher end cutlery they should be avoided in general as they don't allow the true ability of the steels to be seen.

-Cliff
 
Allright, just got through a couple of hard 1x6s and no edge deformation, or noticeable loss of sharpness. I gave it 8-10 swipes per side along a very worn out piece of what was 400 grit sandpaper, mostly to get the residue off the edge, and it is shaving hair off my arm.

Full report:
When I got the Jack it was nearly shaving sharp, with horizontal grind lines on the very edge, and noticeable ammounts of steel missing from the very edge as noted above.
I cleaned up the edge with the diamond side of a Falkniven DC4 (a survival kit must-have) to the point that the missing chunks of edge were barely noticeable. The Jack was still at the barely shaving sharp level.
On to the Edge Pro Apex, where I discovered that I still needed to remove a good portion of metal to expose a new edge devoid of macroscopic imperfections. 180grit, 220grit, 320grit, and finally 600grit got it shaving sharp with no imperfections under a 10x loupe.
18 inches of old, dry, hard 1x6 and the edge was at the barely shaving point, with no imperfections under the 10x loupe. Not a thorough test, but that's all the wood I had, and it was enough to let me know that a few real world wooden obstacles aren't going to be an issue for this user rat. And I do believe it does at least confirm that the heat treat hasn't been affected.
And now I'm pleased to bring the results to conclude this exercise.
Thanks for watching, that's all folks...
 
Well, here she is with a nice edge and some krylon. I used some painter's tape and an exacto-knife to do the redneck digicam. Looks a bit goofy, but with a little more effort it could have potential...:rolleyes:

dbfb062d.jpg
 
JWBirch said:
...When I got the Jack it was nearly shaving sharp, with horizontal grind lines on the very edge, and noticeable ammounts of steel missing from the very edge...
Click to expand...
That sounds like a wire edge. Good job fixing it.
 
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