Couple noob questions

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Peak_Oil

Joined
Nov 6, 2005
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First, I have a little minor surface rust on my CRKT M21-14. I don't know anything about removing rust or really anything about steel. My first thought is to use a little Hoppe's #7 Bore Cleaner to get it off, but I figured it's best if I ask you guys first if that's the way to go. Also, do I use steel wool or what?

I also have a Khukri, one of the cheap surplus $15 jobs. I modified it a little by having the handle ground down to get rid of the ring in the handle, and took it out to get sharpened. I guess they used a grinding belt to put an edge on it, 'cause there's a discoloration on the edge now. It almost looks like a water mark creeping back into the blade from the edge. I gather from my reading that this means the temper is ruined. What does that mean in a practical sense to me? Does that mean I throw it in the garbage 'cause it's dangerous to use now, or what?

I have another couple khukris of the same make. They're very tedious to sharpen because they were not sharp to begin with. The edge is what I would call rounded. It takes quite a bit of time to grind it down to something I would want to use to cut something. Can I use my dremel to grind it down a little, or should I block off a week in August to grind it down with a stone by hand?

And last, I want to blue the blade of this new khukri. Any suggestions on a good cold bluing?

Thanks for any answers, gents
 
Steel wool can take off light rust as can a scotchbrite pad, if it is deep enough and black you may need a chemical remover or sandpaper.

If the blade is discolored that means it is softened. The edge retention will be lower and you will likely have problems with sharpening.

You can use a dremel, just don't grind in one spot for long and don't let the blade heat up. You might be faster with a large bastard file.

-Cliff
 
I've used an cold-blue solution from Gunslick. Just follow the instructions and it works fine. Multiply applications are required, and rinising in hot water in between helps to define the colour. I think I used deteregent, an degreaser, and then acetone to clean it of oils.

http://www.canadiantire.ca/assortments/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524443248908&FOLDER%3C%3EbrowsePath=2534374303517496&FOLDER%3C%3EbrowsePath=2534374303517509&FOLDER%3C%3EbrowsePath=1408474396669584&FOLDER%3C%3Efolder_id=1408474396669584&ASSORTMENT%3C%3East_id=1408474396670271&bmUID=1154033244803



trailhawk.jpg


I've noticed on the Trailhawk that here is a quench line or hamon or something on the edge end and poll end, as the piece is supposed to be differentially heat-treated. I thought these microscopic details can only be brought out when the piece is etched? Could this be what Peak Oil is observing, except in reverse?
 
underaged! said:
I'd agree and say go with a nice sharp file. Dremels suck.
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Dremels are fantastic tools but they have their limitations. Using a Dremel to sharpen a long straight edge, it would be dang hard to keep everything straight and even.
A file is the right choice for this, it's much easier to control.
 
Peak_Oil said:
I guess they used a grinding belt to put an edge on it, 'cause there's a discoloration on the edge now. It almost looks like a water mark creeping back into the blade from the edge. I gather from my reading that this means the temper is ruined. What does that mean in a practical sense to me? Does that mean I throw it in the garbage 'cause it's dangerous to use now, or what?
Click to expand...

If the blade was overheated it will draw the temper meaning the blade gets softer. How much softer depends on how hot the blade became and how long it was held at the elevated temperatures. If it was overheated significantly you will just notice it blunting faster in use. What you could be seeing is just rust, those steels will corrode easily, especially when wet and hot.

Kel_aa, etching is just rust, and the hardened steel rusts at a different rate than the softer steel and thus shows the hardening line. You can see it readily on my Ratweiler which was never intentionally etched, however the patina is way heavier on the spring drawn area than the harder edge.

-Cliff
 
Etching is just rust, and the hardened steel rusts at a different rate than the softer steel and thus shows the hardening line. You can see it readily on my Ratweiler which was never intentionally etched, however the patina is way heavier on the spring drawn area than the harder edge.
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That's an good explaination. Do you think they draw the middle area by heating with locally with a flame or do you think they locally heat the ends to austentizing temperatures and then quench them with say an waterjet (I've read this setup as used for selective hardening of an piece)? The latter seems a little hightech for this product.
 
Khukuris are typically edge quenched, not spine drawn. On the axe, you can usually tell if it was drawn or just locally quenched by the hardness of the softer area. If you draw the temper you usually go to spring hardness, 40-50 HRC. If you just edge quench then the softer part is left in the as-supplied/normalized condition so it is really soft, 20 HRC.

-Cliff
 
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