Teaser for those getting Villager Rehabs

Daniel Koster

Daniel Koster

www.kosterknives.com
Knifemaker / Craftsman / Service Provider
Joined
Oct 18, 2001
Messages
20,978
I started rebuilding my busted-up 22 inch Ganga Ram Special. If you don't know what I'm talking about click here: http://www.bladeforums.com/forums/showthread.php?threadid=257973

I'll post some pics and later, videos, as I make progress on this one.


To start off, here's an overall pic of the knife:

22inchGRS.jpg





A close-up of the chewed up part of the blade:

beat-up-edge.jpg





First thing I did was to draw a new outline and estimate where the bevel would fall - all in permanent marker.


marker-new-edge.jpg






Then I taped up the surface of the blade that I wanted to protect while grinding - with some of that famed 3M blue low-stick tape.




Left Side:

taped-up-l.jpg






Right Side:

taped-up-r.jpg




Now, to the grinder.

Always make sure your belt sander/grinder is square to the tool rest and platen.

check-level.jpg





Here's a video of me grinding away at the blade. Lovely screeching sound that I'm sure the neighbors find pleasing and enjoyable...

You can see me dunking the blade in a #10 can full of water to keep it cool - very important!

Grinding video (465 KB)



After grinding for a minute or two, I'm starting to be able to get a decent profile.

partially-ground.jpg




I keep on going and it takes less than 10 minutes to finish profiling.

I check it to see if there are any rough spots left:

edge-ground-flat.jpg




Looks great!

You can see the grind lines because I used a 60 grit belt to knock it down real fast.


Here's the end result of Phase 1 - Profiling

finished-edge.jpg



After this, I'll move to a 120 belt and start hogging off a new bevel.


Wish me luck!

Dan
 
Just for fun, I took the GRS outside and whacked a 2x4 with it. Result:
(lower cuts)

initial-sharpness-test.jpg



I figured this ought to be good for a before and after set of pics. The interesting thing is that although the khukuri is severely blunted, it still cuts wood. I should add that I was in shorts and bare feet and "held back" a little...:rolleyes:


The marks in the top are from the AK Bowie that is now in Stripey's hands. :D More on that in his test thread.
 
As usual, always interesting, Pen. And yes, that AK Bowie scares me a little. I'm going to get a Sasquatch style sheath for it from the Sarki Shop. Someday my first knife project will be slapping a set of wood slabs on it. The blade is perfect, thanks to you (and Bura of course!)
It's good to see that GRS getting a new lease on life. I'll be watching this with interest. Makes me want to see if my Uncle will let me install a grinder in his basement!
 
Well, it will certainly look better but,

Is the problem due solely to profile?

Do you plan to do any kind of tempering?
 
Dadgum, I didn't know GRS's came in a serrated version. What happened Dan, hack down a thicket of mild steel re-bar?:eek:

Sarge
 
Brendan - check the mugshots page to see me in full garb - dust mask, shop goggles, etc. The dust from these projects is not friendly...

firkin - I'm not set up to heat treat spring steel. From what I gather, the problem is 70/30 = edge grind/heat treat. My suspicion is actually that the chips were made in a part that was over-hardened. This works to my benefit because as I remove more edge, I'm getting closer to the softer part of the steel - which really helps with a convex grind. The real test, however, will be when I'm finished and I take the khuk out and test it on the very same tree. If it comes back unscathed - we'll know it was the edge grind.

Sarge - click on the thread at the top of the page. Serrated? Oh yeah...! I even used it to....(well, go and see) :D
 
Dan, I wasn't thinking of a full heat-treat.

Since it readily chipped, it seemed that over-hardening was a possiblity, and that a simple tempering in the kitchen oven could bring the hardness down a bit.
 
How thick is the new profile before you start to convex. It looks like it's 2mm or so in the pic give or take a little due to the comparison to the thumb.
 
That's a lot of metal. From the pic again the blade looks like it loses about 3mm of edge material to get the proper grind (for that knife). I guess I have to look at getting some sort of powered tool for sharpening.

Or at least for profiling.
 
About 12 years ago in Guatemala, I found myself with a machette in one hand and a file in the other, and no clue what to do to sharpen it. I had watched the locals sharpen their machettes with triangular files, so I set about doing the same.

The blade was about 3/32" thick and it took 2 hours of solid filing to get it down to a sharpened bevel about 1/4" wide.

It can be done by hand - but I'll never forget the "day after" - that was some serious hand pain.

I think that if you were to clamp the rascal down in a woodworker's vise and file it with a double-cut mill bastard file, you could surely grind it down as well as I did in probably half-an-hour. Get a good Nicholson file.

Hmmmm...now that's an idea...maybe I'll give it a shot on the chipped villager coming my way. :cool:
 
A fine incentive for posting more villager deals, don't you think, Uncle Bill?
 
I spent some more time at the grinder yesterday. Took about an hour to get this done, but well worth it.


Disclaimer: For those of you out there desiring to put on a convex edge yourself, remember to take it slow and not give up. Reason I say this? It's easy to get frustrated and feel like the grinder's kickin your butt. I always get butterflies before grinding, but after about 15-20 minutes I settle into a groove and I can grind much more consistently. Sometimes it's hard to see the progress, but as long as you're pressing it against the belt, progress is being made. If you've got time (and I got plenty) then just wait it out. At one point, I was just barely touching the blade to the belt in order to remove some light scratches, high on the bevel. Patience, patience and more patience!


Whew!

Ok, let's get to the results. :D



just-getting-started.jpg



As you grind the convex edge, if you're doing it right, it will start to remove the top of the bevel before the middle. ;)



almost-done.jpg


Here I'm pointing out (in this fuzzy pic) how the edge of the bevel (A) is ground with no scratches, while there are still scratches on the upper part of the bevel (B). This is the part that really kicks your butt. :D



finished-bevel.jpg


Another blurry pic :rolleyes: but now the bevel is finally finished. The wavy line on the blade is water spilling back after I pulled it from the bucket.


By the way, this edge was put on with a 120 grit blue zirconia belt. Here's a video of me grinding:


http://www.pendentive.biz/blades/grinding2.wmv

See how I'm using a "sawing" action? Always edge down when slack belt grinding.


Let's pause here for a minute and review some grinding facts. If you grind against a platen (metal piece backing the belt - perpendicular to the tool rest) or against a wheel, you will leave deeper scratches than if you slack belt grind. That how I get such a nice polish at 120 grit. By the time I'm done putting on the bevel, I'm barely touching the khuk against the belt.

In order to properly achieve a convex edge (and not take all day) it's best to start with multiple flat bevels first and then just round 'em over. Make sense? Think of how you can easily turn an octagon into a circle by rounding over the corners. That's the idea here.

As noted above, in order to get a flat grind, you need to grind against a platen. Here's where I cheat. :D I place a piece of heavy leather doubled-up, between the platen and the belt. This way, it cushions the platen, lessens the chatter and doesn't make those deep scratches.

I'll try to post more grinding tips as I think of them.



Just for fun, I swung it at the ole 2x4. Here's the result:

wood-test.jpg


Nice cut, eh?

I took it back inside and it shaves hair. And I only used the 120 grit belt!!!

That's the kind of performance you can expect from a convex edge. Just putting the edge on a knife sharpens it automatically.
 
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