Bent Pocket Knife Blades

[Trout Hound]

"Bob, I have given a name to my pain." I'm not talking about blades bent through abuse, but rather the ones that are bent from the factory to fit beside each other when folded, but work on the same spring.

I've been messing around with a knife my wife has had for a long time, a Schrade USA Old Timer 104OT. It was pretty dull, so I took it to a Japanese waterstone. I fooled with it off and on for two days, and thought I was losing my mind, because I just couldn't get the thing to apex cleanly. Then, I finally turned the blade up and looked down on top of the spine. That's when I realized: I was sharpening a curved blade on a flat stone. No wonder it was being such a pain. The blade is hollow on one side and bellied on the other!

None of the knives I regularly carry are configured this way, so I'm not used to it. How in the heck do you guys deal with this? I'm thinking that a diamond or ceramic rod would be a lot easier to work with on such a blade. I even turned the stone up and took some very light strokes against the corner, but that probably isn't the best solution.

What? Help!

 

[Copenhagen55]

I'm sure I'll catch plenty of crap from the old timers on here that believe in nothing but using a stone in their rocking chair on the front porch... But get a Worksharp Ken Onion edition. I've sharpened every blade in the house from my hatchet and parang, to a recurve Camillus and all my hunting knives. Usually the day after I sharpen the kitchen knives I'll come inside and my girlfriend will have a new band-aid, or four last week... And she'll just look at me and say "You sharpened the knives without telling me again..." haha puts an AMAZING edge on everything you can think of.

 

[abbydaddy]

The blade itself is bent instead of being crinked? That blows. And I have zero useful advice sadly.

 

[Obsessed with Edges]

Might post a pic of the blade with which you're having trouble. Depending on how curved/bent it is, you might get different advice as to what'll work best.

For what it's worth, my favorite traditional pocketknife pattern is a stockman. The vast majority of those are built on two springs with 3 blades (clip, spey/pen, sheepsfoot); and on most, the sheepsfoot blade is 'crinked', a.k.a. 'bent' in order to fit it into the frame. I've found that trailing-edge sharpening on wet/dry sandpaper over a somewhat forgiving backing (thin leather, or a couple or three sheets of paper over a hard backing) is a relatively easy way (maybe easiest) to make the abrasive surface conform or shape itself to the curvature/bend of the blade. You still won't get perfect bevels this way, as the bend of the blade will still dictate which portions are ground more heavily. When the curvature has the tip and heel of the edge 'down' into the abrasive, the tip & heel will be ground more heavily; when turned to the other side, with tip & heel curved upward, the area between the tip & heel will get the most contact, and will therefore show more effects of the grinding. The upside is, you can tailor the conformability of the backing under the sandpaper to more closely fit the curvature of the blade. When using sandpaper this way, the bevels will be somewhat convex, because of the slightly softer backing. Nevertheless, it's still a decent way to get the entire edge apexed and sharp; and even easier at a lower held angle. Practice stropping on a bare leather strop (hard-backed) to get a feel for how the leather sort of conforms to the curvature of the blade; then just add the sandpaper over the leather, and use the exact same stropping technique with it (this is exactly how I learned to do it, after practicing my stropping technique for some time; the transition is very easy). You could also use the same edge-trailing technique on sandpaper wrapped around a fairly large-diameter cylinder, as is often recommended for sharpening recurved edges on blades.

The other way to do it on a stone, is to make sure your stone is ever-so-slightly radiused (rounded over) along one edge, just enough to let the curvature of the blade sort of 'wrap around' the edge of the stone, without the downside of edge damage that might be done if the blade's curved edge were scrubbing on a hard-cornered edge of the stone. Use the tip/pad of your index finger to exert some light pressure on the specific portion of the edge being worked; this helps you feel that the edge under your fingertip is making flush contact on the stone, and it's easier to make sure it gets the work it needs. The radiused edge of the stone will allow you to work on different portions of the edge, while minimizing over-grinding other portions not needing it. For example, the tip of the blade can more or less be laid flat to the stone near it's edge, allowing the curved portion of the blade's edge behind it to arc over the edge of the stone without being over-ground. When working the central (usually the most curved) and heel portions of the blade, the radiused edge of the stone can be more fully utilized for that, while allowing the flatter tip portion to be lifted away from the stone. All of this CAN still be done on a dead-flat stone; I've used flat diamond hones to set bevels on a lot of my traditional pocketknives (main thing is to use your fingertip to ensure flush contact on specific portions, as I mentioned). BUT, having a stone with a radiused edge will make it easier.

BTW, one of my stockman knives is a 108OT (pic below), which is the 3-blade stockman built to (what I believe is) your 2-blade 104OT pattern handle (2-3/4" serpentine). If your clip blade is like the one on my 108OT, it should also be pretty thin & flexible, which might aid in ensuring flush contact on a stone, IF you're using a fingertip as I mentioned above. My clip blade is also curved, BTW. On very small & thin blades like these, it's very, very common.


David

 

[Copenhagen55]

I know it's way more expensive than a stone,mbut also much more effective and time saving. With the Worksharp the belts will just conform to the blade instead of having to bend the blade flat to a stone.

 

[davek14]

On the plus side, that should be some nice, forgiving steel to sharpen.

 

[Obsessed with Edges]

I know it's way more expensive than a stone,mbut also much more effective and time saving. With the Worksharp the belts will just conform to the blade instead of having to bend the blade flat to a stone.

If his knife is scaled to the same frame as my 108 OT, the 'large' blade (clip) on it is ~1.75" long (cutting edge), 0.30" wide from spine-to-edge, 0.05" thick at the spine and 0.01" thick just behind the edge bevel, in very easy-to-grind 1095 steel (or 440A, if it's stainless; also easy to grind). Ordinarily, I'm sure the Worksharp is a handy tool for larger & thicker blades; but in inexperienced hands, it'd wreck a tiny blade like that very fast with one slip-up. Not to mention, the little bit of pressure exerted, to make the belt conform to the blade's curvature, would also be more than enough to overgrind the edge in a second, on a moving belt.


David

 

[SOFileworks]

Actually a WorkSharp with the guides removed and a used red belt should work just fine...just don't use the green one or you'll have nothing but a very sharp toothpick.

 

[Bighaze51]

I little trick I learned from sharpening straight razors is to rock the blade. I'm not really sure how to explain it but you basically start at the base of the blade and drop your hand down so the tip of the blade is in the air. As you are perfoming the stroke, gradually lift your hand so the blade "rolls" towards the tip. Just look on YouTube for sharpening a warped razor and you'll get it. I really don't understand how it works but it does. It will work with a bent knife blade too.

 

[Trout Hound]

I actually didn't know that "crinked" was the correct term, so thanks for teaching me. I'm pretty sure that this, however, is just plumb bent!

 

[Obsessed with Edges]

Near the tip, if I'm seeing it correctly? If so, that's just like the bend/curve in my 108OT's clip blade, and in the same direction. I suspect it's more a factory warp than a bend (as if damaged later). I think both of these patterns probably share a common clip blade profile & size, so there might've been something about the manufacturing or grinding process creating the warp in it.


David

 

[Trout Hound]

Yes, it is most pronounced at the tip, but there is at least some curvature across the entire length, all the way down to the heel.