Sharpening Questions... again....

R

Radrunner

Joined
Mar 6, 2006
Messages
234
Even after the recent post that briefly touched on sharpening of khuk's, i still have quite a few questions...

I know the rough idea of sharpening khuks since they have convex edges, particularly the mouse pad methods and using the leather strop.... but a few more questions i was hoping i could get a more direct answer to..

1) Making a leather strop:
-You glue two pieces of leather on either side of a piece of wood, yes? or at least that's how i've seen them done in all the images i've tracked down...
-How subtle/soft should the leather be?
-How thick should the leather strips on each side be?
-Where can i find the two compounds you rub onto each piece of leather?

2) Mouse-pad method:
-How thick does the mousepad have to be?
-How soft does the mousepad need to be? I'm assuming a gel pad would work better than a laminated plate, which would defeat the entire "give" purpose.
-What grade(s) of sand paper should i go for?
-Do i still need a leather strop to do the final touches after the mousepad method?

3) Can you buy leather strops? and how much do they cost if you can (though i'd prefer to make off an old belt)

I've heard it is possible to sharpen a convex edge with a wet stone... Anyone have more information on this? It's more of an interest thing - i'm not about to pull out my stone and potentially ruin the edges on my khuks (dull as they might be). That said, I haven't been able to find any other information on this method on youtube or searches...

Thanks in advance guys and gals! I know some of this stuff seems like a stupid question, but all my knife experience up to HI has been with bevelled edges (?) ... so all the sharpening has been done with a wet stone. Given i want to preserve the convex edge on the khuks, it's time to expand my sharpening methods.
 
Radrunner said:
I've heard it is possible to sharpen a convex edge with a wet stone... Anyone have more information on this?
Click to expand...

I use a stone to sharpen all my convex edges, and then strop to polish them.
Easiest way is to hold the blade still and move the stone with your other hand. The natural motion of your hand will convex the edge. That'sa well-known "secret" that if you sharpen by hand without using guides, you will eventually convex the edge. Not the whole thing from edge to spine, but the final bevel where you actually sharpen, will become convexed over time.
 
Take this for what it's worth (probably not much), but, I have had great success using my Spyderco Sharpmaker on all my khuks. I tried the mouse pad and sandpaper, but just couldn't get the results I'm used to getting on my other blades with the Sharpmaker (hair whittling sharp). I found using only the medium (brown) stones actually gives me the best results. On my smaller EDC knives, I almost never use the browns and just use the fine, ultra fine and a loaded leather strop, but for some reason, using the finer stones doesn't give the same results on the khuks. But I DO get them hair-popping sharp using just the Sharpmaker and the brown stones. YMMV.
 
so, punishment, what kind of angle should you hold the stone at, and should you move it, hold it constant, or keep it loose?

This sounds like a good way to finish my project without wasting too much time.

Remember my thread bitching about edge damage on my NKH british army?

Well Ive decided to grind the tip all the way down to where the damage is, reducing the bulge between the tip and sweet spot a bit so I don't have to bring the whole edge down, problem is with just 360 grit paper it is taking FOREVER.

Oh yeah, is there any way to get rid of scratches, or un-matte the edge from low grit sharpening, or should I just scuff up the whole edge to give it kind of a two tone look?
 
I hold the stone in my right hand, and hold the blade still in my left.
Going from edge towards the spine, I push the stone across the area of the final bevel to the edge. I start at an angle a little more obtuse than the angle that is there, and as I push, my wrist naturally flattens out the angle on a curve as I go. That's to establish the convex. Once you have the convex you want, it's just a matter of following the curve with the finer stones and then a strop.

Now, doing this with stones takes a long time, also, it would be much quicker to use a belt sander, or to send the blade off to someone who is good at it, then maintain the edge on a strop.

Finally, as for the finish on the sharpened area. When you strop it, it will end up polished -- usually shinier than the rest of the blade.
 
Cpl Punishment said:
Easiest way is to hold the blade still and move the stone with your other hand.
Click to expand...

Before I try to apply that advice, may I ask what size and/or configuration of stone(s) you're using? You see, what I own is one of these.....

sharp_tri8_1_600.jpg


.....and being as large as it is (8' long), I'm not sure that moving it, while holding the blade stationary, is really feasible. Are you using, smaller, hand-held stones of some kind?
 
No, I use an 8" Norton India stone fine/coarse and a Knives Ship Free strop. The large stone is nice, as it keeps my fingertips away from the edge.

;)
 
Strop sticks can be made from very inexpensive materials found at your hardware or craft store. Get a 1" wide piece of lathe. The thickness of the lathe should be about 3/8" to 1/4".
Cut it to 10" in length. Sand it to remove splinters and rough spots on the edges.

Next, shape an "hourglass" curved inset on one end with a pocketknife, dremel or chisel. Make the curved inset on each side of the stick even. You can whittle this by eye if needed.

Purchase a strip of 1" suede leather at a craft store. Here in Wisconsin we have an outlet called Hobby Lobby. I got a yard of material for about three bucks. Cut this length of leather to 6" and epoxy it to the stick. Be sure to bond the epoxy to both the leather backside and the stick before clamping. Why suede? It holds more compound and lets you strop longer between resaturating the strop.

I use a 0.5 micron Green Chromium Oxide stick purchased at Lee Valley woodworker's supply. http://www.leevalley.com/wood/page.aspx?c=2&p=32984&cat=1,43072
$10.50 plus shipping. Lasts a long time.
 
Cpl Punishment said:
I hold the stone in my right hand, and hold the blade still in my left.
Going from edge towards the spine, I push the stone across the area of the final bevel to the edge. I start at an angle a little more obtuse than the angle that is there, and as I push, my wrist naturally flattens out the angle on a curve as I go. That's to establish the convex. Once you have the convex you want, it's just a matter of following the curve with the finer stones and then a strop..
Click to expand...

Does this mean that you don't run the stone from tang to tip? Just from edge to spine?

Also, can you use a honing compound to return a lightly scratched blade to mirror?

Trying to regrind my tip with 360 grit sandpaper, I have turned most of the edge completely matte.
 
Yes, good questions. I'd like to know if I did anything wrong.

You see, I tried the "moving stone, still blade" approach just a couple of nights ago, and it helped, but then I tried another method, stroking it backward on a stationary stone (like stropping, almost), which did just as well, and was less tiring. However, I was moving in both planes, and if that's wrong, I may have made things too complicated.
 
Good tips from everyone!:thumbup:

Personally I prefer my strops a bit thicker and cut mine out of a piece of '1" by' such as a 1"x 2" although I do prefer a strop that's less wide for khuks because it makes it easier to transcend from the recurve to the sweet spot although a 1"x 1-1/2" will work a narrower strop works easier, IMHO anyway.:)

I also prefer two strops to one because then it's possible to lay them most anywhere without your other half swearing at and cursing you, that is unless the last place you set it down was covered in something nasty as it's just wood on the back side and not a strip of leather with some sorta dirt on it...;)

Another place to find leather for your strops is Tandy Leather Company or another commercial leather dealer in your area, look in your phone book, you might be surprised. I prefer a new clean piece of leather to an old belt for many reasons but the main reason is that there's never been any sorta leather finish on a piece of carving leather or a belt blank which makes it easier to load with a stropping or honing compound or grit... Depending on the length of the belt blank or leather strap you get depends on how many strops you can get outta it so choose wisely.;)

I use my strops by laying the khukuri flat down on a table with what I can get of the edge laying off over the side of the table and then holding the khuk as stable as possible I push the strop at an angle from the spine to the edge and along the edge at the same time while gently raising up the back of the strop, making two motions into three sorta, capiche? ;)

As to whetstones... sometimes you can pick up what I call, "paddle hones" which is a thin whetstone glued onto a thin piece of wood that's long enough to have a handle beyond the stone itself... You can use these the same way I use a strop... But I much prefer one of the DMT Duofold diamond hones...:thumbup:
And stay away from the green ones as they are much too fine, actually IMHO the red ones are sometimes too fine after they're broken in...
I've found the blue ones to be about right for field sharpening, after they're broken in of course. :cool:

The one thing you wanna remember about fully convex blades though is that they're like what some folks call a, "Scandi edge" in that the whole blade is a convex and to hold the original radius or close to it then you have to sand, stone, hone, or whatever method you use the whole blade and not just the edge...
And that's why convex edges are easier to maintain than convex knives... :p ;) :D




.
 
A method I have found works really well:

Use a bog standard rubber sanding block. I've recently found a fancier one which is larger. has a closed cell foam type backing and actually clamps the wet and dry paper on either end.

Start with a coarse grade 120 grit for the first sharpening to remove the softer outer steel quicker. (The quicker you remove the outer steel the less tired and bored you'll get and the more true your sanding angles will be)

Progressively work with finer grits (120 to say 360 to 600 to 800 to 1200 etc)

Stabilise the blade by pressing the tip into a wooden chopping block and sand the entire bevel from where it curves midway accross the blade down toward the edge (standard SOP for convex sharpening) be consistent and develop a rhythm.

Turn knife around so pommel is resting on the chopping block and sand the area leading to the tip in the same fashion. BE CAREFUL as you will be holding the blade at this point use a leather wrap to prevent cutting your hand.

The natural motion if you develop a smooth rhythm will give a perfect convex, use a relaxed grip on both blade and sanding block! Do not run the sanding block off the edge of the blade as this will stop an edge from being created, lift it before the end of the block runs off the edge!

The blade will look ugly at this point and you will have noticed high and low spots brought out by the forging process you can smooth this to a certain extent by sanding along the length of the bevel ie from tip to blood groove.

I usually finish the entire blade by hand with progressively smoother grades of sandpaper and then scotchbrite to a satin finish that looks pretty good as the sanding and sharpening process destroys any mirror polish.

You can finish off with a leather strop and compound to polish the edge. This should give an edge that will almost shave but will slice paper, leather and meat cleanly and smoothly and give polished cuts deep into hardwoods yet still be strong and last very hard use without damage.

I learned this method through loads of lurking and reading tons of info on how to sharpen convex blades and practicing on various Khukuris. It took awhile to develop the right feel but now works like clockwork!
 
Last edited:
Re: stropping - since I'm too cheap to get a dedicated leather strop, I decided to try using denim jeans instead, and my blades have never been sharper. I strop while wearing the jeans, and the give of my leg's flesh has the same edge-accommodating effect as the mousepad under sandpaper.
 
C.S. Graves said:
Re: stropping - since I'm too cheap to get a dedicated leather strop, I decided to try using denim jeans instead, and my blades have never been sharper. I strop while wearing the jeans, and the give of my leg's flesh has the same edge-accommodating effect as the mousepad under sandpaper.
Click to expand...


Hmmm........... This might the explain the wee shallow slice in the upper lt thigh of Doc's jeans....and Yes, also on His upper thigh there is a wee little , very clean- looking cut that is rapidly healing.

I'll have to ask Him about it and see what He says!;)

Ahhh....The trials and Tribulations of Blade Ownership!

Willow
 
Conor09 said:
A method I have found works really well:

Use a bog standard rubber sanding block. I've recently found a fancier one which is larger. has a closed cell foam type backing and actually clamps the wet and dry paper on either end.

Start with a coarse grade 120 grit for the first sharpening to remove the softer outer steel quicker. (The quicker you remove the outer steel the less tired and bored you'll get and the more true your sanding angles will be)

Progressively work with finer grits (120 to say 360 to 600 to 800 to 1200 etc)

Stabilise the blade by pressing the tip into a wooden chopping block and sand the entire bevel from where it curves midway accross the blade down toward the edge (standard SOP for convex sharpening) be consistent and develop a rhythm.

Turn knife around so pommel is resting on the chopping block and sand the area leading to the tip in the same fashion. BE CAREFUL as you will be holding the blade at this point use a leather wrap to prevent cutting your hand.

The natural motion if you develop a smooth rhythm will give a perfect convex, use a relaxed grip on both blade and sanding block! Do not run the sanding block off the edge of the blade as this will stop an edge from being created, lift it before the end of the block runs off the edge!

The blade will look ugly at this point and you will have noticed high and low spots brought out by the forging process you can smooth this to a certain extent by sanding along the length of the bevel ie from tip to blood groove.

I usually finish the entire blade by hand with progressively smoother grades of sandpaper and then scotchbrite to a satin finish that looks pretty good as the sanding and sharpening process destroys any mirror polish.

You can finish off with a leather strop and compound to polish the edge. This should give an edge that will almost shave but will slice paper, leather and meat cleanly and smoothly and give polished cuts deep into hardwoods yet still be strong and last very hard use without damage.

I learned this method through loads of lurking and reading tons of info on how to sharpen convex blades and practicing on various Khukuris. It took awhile to develop the right feel but now works like clockwork!
Click to expand...

I use a similiar method. The water paper does not last long but it is consistant.
I just use 240, 400 then 600. After that, compound on a bit of leather makes it razor sharp.
The edge comes to a near mirror polish
 
I use a large flat stone to do most of the blade and a curved stone to sharpen curved edges - the recurve. Norton makes a large India gouge stone, and it is large for sharpening large curved edges. YOu should be able to find one at places like MSC.

Lee Valley sells these in the form of waterstones:
http://www.leevalley.com/wood/page.aspx?c=2&p=33012&cat=1,43072,43071&ap=1

I know that you could use these for the recurve:
http://www.craftsmanstudio.com/html_p/N66253-064728.htm

You could also wrap fine abrasive paper around large dowels to finish the recurve. Flat stones work for the rest of the blade.
 
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