Sharpening the harder blades...

BruiseLeee

BruiseLeee

Joined
Sep 7, 2001
Messages
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Last week Uncle Bill put up for sale a couple of 18" WWIIs that were harder than "normal". These were returned by folks who had difficulty sharpening them.

My theory is that it would just take more time to sharpen these.

How will the extra hardness affect the blade and the durability? Are they more likely to chip? I figrure that the edge will last longer and they will be perhaps more likely to chip depending on how much harder they are.

Is this correct? :confused:
 
Harder blades would take longer to sharpen, but it shouldn't be much of a problem with modern equipment. It also helps to have a little better feel for what you're doing - to stay consistent and not get frustrated with your progress.

Harder blades can support thinner edges, and resist rippling or bending - like some of the rolled edges that showed up about a year ago with the Maoist trouble. Too hard, though, and the edge starts to chip out if you hit rocks or knots. Also, prying or other side-to-side movements with a hard, thin edge could cause serious damage. Given the really thick edge of a khuk, chipping shouldn't be a huge problem in everyday outdoor sorts of applications.
 
They weren't all that hard; I think Bill said RC 61. The site says up to RC62.

Most people want the higher rockwell. I remember a special that sat for a week or so with an RC of 57 during the Maoist uprising.

Bruise, a knife expert will arrive here shortly, but I kinda doubt the RC of 61 is going to chip any easier, than you or I could tell, than one at 59.

I noticed quite a while ago Bill stopped listing the RC.


munk
 
Bill, I noticed there was a manufacturer's forum, where you guys could talk to one another in privacy from your public. I tried to log in there by mistake today. I assume a red flashing strobe went off on your desk at Titanic ll.

What do you all talk about there?

"We have the most modern CNC machinery." The Other Manufacturer.

"We have strong right arms." Bill Martino





munk
 
Munk there's alota difference between a couple of RC points. Files are only at RC 64 abouts. You can really feel it when you try sharpening an edge that is around RC 60. However, I personally like harder edges. I had one bolo, had the highest hardness of any knife Ive had. I had to try and take the hardness down with a torch before I could even touch it with my diamond stones. But since, like HI products, its zone hardened, this puppy is sturdier than heck. The nice thing about high RC blades is that they take and hold an edge that just cannot be attained at lower RC. Because at lower RC hardness the edge is just too soft to take ultra fine sharpness. And they stay sharp like crazy. Though, it is a pain to sharpen them. Soft stones, like Arkansas stones wont even touch the edge.
 
Originally posted by Federico
The nice thing about high RC blades is that they take and hold an edge that just cannot be attained at lower RC.
Click to expand...

Or they take and hold the dullness that just cannnot be attained at lower RC. :(

At least I know it's not just me then.
 
Another question though...

Does one get the harder edge by cooling the blade quicker or is it the other way around? Also do the kamis do this to punish me or is the cooling process hard to control with just wrist action and a kettle of water?

:confused:
 
as usual; what do I know?


Put that on my tombstone. "What did he know?"



Bruise, I'm with you on keeping a good hard dull edge dull. I have a Browning SS hunting knife I didn't think i'd ever get sharp. It wore down appreciably a diamond EZ lap.



munk
 
In general you get a higher hardness by a more extensive soak, faster quench and a generally a lower tempering temperature, however the high alloy steels have very intricate temperature dependencies and can break many rules.

The harder steels are no more difficult to sharpen with decent abrasives assuming they don't lack the necessary durability to prevent chipping. Even 60+ RC steel is butter soft compared to SiC or AO, the two most common abrasives. Use decent hones, not the ones with heavy masking bonds like the India stones.


-Cliff
 
When I try and sharpen my Bura WWII, instead of taking metal off the blade it takes the grit off of my lansky hard stone. Now I'm thinking I'll have to use a file. Are there other alternatives? Would sandpaper work?
 
Not really a stone, but a seriously hard sharpening implement. also, there are certain ultra-hard stines in use in machine shops and tool and die shops, so ask around about how to obtain these. The best way is to have someong in the mill get you a broken one. The broken or chipped ones are of no use to them, and end up being thrown away oftentimes. I scored a 3x8 inch two sider (medium and fine) fromm a buddy who worked at such a shop. only a bit of the corner was chippped out. I've been using the dang thing for 13+ yeasr, and it is only now showing signs of wear. The loading is a bigger problem, and the stone must be kept meticulously cleaned and watered.

Keith
 
I just planted a Black Hills pine in my yard. I watered that.


.. ...

It is always great to see Cliff Stamp around.



munk
 
Originally posted by Vicks
When I try and sharpen my Bura WWII, instead of taking metal off the blade it takes the grit off of my lansky hard stone. Now I'm thinking I'll have to use a file. Are there other alternatives? Would sandpaper work?
Click to expand...

A sharpening stone *should* be much harder than steel, but the grit is bonded together. I'm not sure if it's glue, or fused or what, but it sounds like you have a problem with the bonding material. Then again, very coarse stones tend to come apart more easily, because the grains are large and relatively far apart.

So any sort of silicon carbide, aluminum oxide or diamond thingy should work. Unless this is part of khukuri mysticism, in which case you may need to do a ceremony. :eek:
 
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