Sharpening my Kershaw Thermite with a Lansky sharpening kit?

K

kensclark16

Joined
Sep 25, 2013
Messages
17
The kit has a coarse, medium, and fine stone. How do I use the honing oil? I applied 2 - 3 drops to the center of the stone but I can't seem to remove the metal powder that is on the stone. What angle is the best? I tried it on a cheap knife set to a 25 degree angle and it was sharp but not that sharp. Should I go to 20? It has an angle setting for 30, 25, 20, and 17 degrees.
 
You could probably benefit by using a more liberal application of oil. Before doing that, clean the hones with some comet/ajax + water and an old toothbrush or similar device. If the stone is really clogged with swarf, Bar Keepers Friend powder + water will work more aggressively (with oxalic acid, which dissolves the swarf) to remove it.

The idea behind using the oil is to use enough of it to 'float' the swarf away from the stone, in use. A couple or three drops on the stone likely won't be enough to do that, so it's better to keep the stone visibly 'wet' with a liberal application of oil. Re-apply oil as needed, to keep the surface wet. As mentioned above, do this after making sure the stones are clean first.

Sharpening angle is up to you. I generally use the lowest reachable angle, depending on what the blade's width will accommodate (narrow blades sometimes won't allow access to the edge at low angles, when clamped). If you find that the finished edge isn't as durable as you'd like it to be, then apply a small microbevel with just a few strokes at a higher angle, using a grit that's suitable to your finished edge preference. On the next major sharpening, you can then use a higher angle to re-bevel the edge (if you wish; a microbevel usually serves well, however).


David
 
If your kit has the Arkansas stones, just rub a drop of oil around the stone with your finger. You just want the stone moist, not dripping. For clean-up, repeat the rubbing of another drop or two and wipe with a shop rag. Some obsess over cleanliness and more power to them if they enjoy it. I've been cleaning the same stones for 40 years and don't see any appreciable build-up of scrap metal on them. They are not perfectly clean, but are functionally clean. They do their job pretty much as they always have. You may, if you choose, after a period of use, clean the stones with detergent and brush or scrubber. Re-oil afterwards.
 
The standard stones are not Arkansas; Lansky offers those in another kit, labelled accordingly. The standard stones in the 3-stone or 'deluxe' 5-stone kits are very prone to clogging, and more so on stainless steel (the OP's knife is 8Cr13MoV, if the specs I looked at are accurate). They're man-made stones, maybe in corundum/aluminum oxide. I have a set; keeping them clean of swarf is important (very). They can even be somewhat slow when new, and if the swarf builds up much, very slow. They're a primary reason I upgraded to the diamond kit. Lansky's hones are all very small, and the extra aggressiveness of the diamond hones makes a significant difference in working speed.


David
 
Last edited:
I used Comet and the Bar Keeper's Friend and the fine stone still feels smooth in the center and the medium one to a lesser degree. Should I just sharpen like normal and hope the smoothness comes out?
 
Also, will the blade be stronger if I sharpen with 30, 25, 20, then 17 or the other way around so there are a lot of micro bevels will that get it close to a convex ground?
 
kensclark16 said:
I used Comet and the Bar Keeper's Friend and the fine stone still feels smooth in the center and the medium one to a lesser degree. Should I just sharpen like normal and hope the smoothness comes out?
Click to expand...

This is what I didn't like about the standard stones in the kit I used (before upgrading to diamond). For some reason, they do seem to glaze over, which is probably the 'smoothness' you're seeing. Which grits are you noticing this on? I ask this, because the problem seemed worse on the coarser stones (XC/C) in my set. My medium stone seemed to do OK, as compared to the others.

David
 
kensclark16 said:
Also, will the blade be stronger if I sharpen with 30, 25, 20, then 17 or the other way around so there are a lot of micro bevels will that get it close to a convex ground?
Click to expand...

'Sharper' is much, much easier at lower angles, generally. To be as sharp as possible, you want the actual cutting edge as narrow in angle as possible, while still being durable.

In using multiple bevel angles to convex, the edge will only be as sharp as the widest angle setting used (30, in this case). All the lower angle settings will only affect the metal behind it (the shoulders of the original bevel). I honestly don't think convexing by using multiple bevels at decreasing angles is worth all the work required, because the lower angles will only remove material behind the edge, without altering the edge angle itself. Lots of work for very little gained in return, in other words. I like convex edges, but I just start with a low-angle V-bevel (17, if possible with your blade on the Lansky), and then over time, I'll use wet/dry sandpaper with a stropping stroke (freehand) to gradually convex it. Starting with a low angle is desirable when doing it this way, because convexing usually will tend to widen the finished edge angle a little bit. This can be minimized or avoided, if care is taken to just convex the shoulders of the V-bevel, without touching the edge itself.

In your situation, if I were doing it, I'd just sharpen the knife to the '17' setting, and then use it. Don't worry too much about convexing it, just for the sake of doing so. Over time, you'll figure out if the edge is durable enough, or not, for your uses. Unless you're using the knife REAL hard, I'd bet you'll be happy with it at the narrower angle. Most any knife in modern steel (including competent heat treat) will usually do pretty well at 15 per side (30 inclusive). At wider angles, the edge can be more 'durable' in terms of retaining it's shape, but may not be as sharp as you'd like it to be, due to the wider geometry. I always choose greater sharpness, myself, so I'm willing to do more frequent touching up to keep it slicing like a laserbeam. ;)


David
 
Last edited:
So will the stones still work with the glaze over them? I only noticed this happening on the fine and medium stone with barely any change on the coarse.
 
kensclark16 said:
So will the stones still work with the glaze over them? I only noticed this happening on the fine and medium stone with barely any change on the coarse.
Click to expand...

Best way to know is to try them. Some brand new stones will lose some surface roughness after some use, but it doesn't necessarily mean they've gone bad (diamond hones do this as part of a normal 'break-in' period). If they are glazed, with some steels that have higher wear-resistance (high carbide content), the glaze will be more of a problem. With simpler steels, it may not be as bad. If you find that your coarser stones aren't effectively removing steel, it may be worth supplementing your kit with a coarse/xc diamond hone, for the heavier grinding tasks. The finishing work can still usually be done with less aggressive or worn stones.


David
 
Last edited:
You should be able to use water to wet the stones. It works as well as oil in my experience and is practically free.
 
Well I just sharpened a knife with the kit. The coarse stone worked but did not form a glaze. After I properly applied oil to the medium and fine stone, I could wipe the metal dust from the current sharpening right off although the old dust did not come out. It works great though! When I get me Kershaw Thermite on Wednesday next week through Monday the week after, should I resharpen the blade with a new angle or leave it at the current angle until I wear it down?
 
When I sharpen at a 17 degree angle, my knife must be too short because the stone grinds on the aluminum clamp. I can still sharpen by only using the end of the stone though.
 
kensclark16 said:
Well I just sharpened a knife with the kit. The coarse stone worked but did not form a glaze. After I properly applied oil to the medium and fine stone, I could wipe the metal dust from the current sharpening right off although the old dust did not come out. It works great though! When I get me Kershaw Thermite on Wednesday next week through Monday the week after, should I resharpen the blade with a new angle or leave it at the current angle until I wear it down?
Click to expand...

Your choice. Hopefully you'll get a factory edge that's good, or at least usable, when your knife comes in. If it isn't, and if you're like the rest of us, it'll be hard to restrain yourself from re-bevelling it right away. :)

It's good to hear that your 'test knife' sharpened up well. :thumbup:


David
 
kensclark16 said:
When I sharpen at a 17 degree angle, my knife must be too short because the stone grinds on the aluminum clamp. I can still sharpen by only using the end of the stone though.
Click to expand...

Sometimes that'll be the case. I think with my knives, a blade width that's less than 1/2" or so is about the limit, in being able to reach the edge with the '17' setting. I use the milled notch in the edge of the clamp's jaws for very small/narrow blades, which helps. I think I used the '20' setting for the guide rod, to sharpen this one:

David
 
Last edited:
You must log in or register to reply here.
Back
Top