ESEE 4 Mystery Steel Pass Around----all spots taken

I'm no longer on the ol' homestead turf I used to be, so I'm not getting round bales at the moment, but do you have a picture of the kind you use? I can think of a few different types off the top of my head.

 

I can do that. It is hell on a blade.

 

I always used a hay knife for opening round bales and it was never that big of a problem getting through twine or netting. The hay, on the other hand, seemed to be the biggest culprit of dulling. I rather expect that the plastic itself isn't what's blunting the knife as much as fine dust that's been ground into it during baling. You probably wouldn't get the same results if cutting fresh unused baling material, whatever the format.

 

I know for what I do I have found the toothy edge on VG10 to be far superior to stainless steels such as all the "holy grail" steels such as S35V.

 

Toothy edges (but no burr or wire edge--still crisp!) give much improved edge retention in slicing tasks, so that shouldn't be any surprise. I often keep my cardboard-cutting edges at ~120 grit with the apex lightly buffed with a sintered ceramic just to get it nice and crisp.

 

Yeah a polished edge would be totally the wrong configuration for those tasks.

 

So, are we saying a highly polished scalpel or razor blade would not cut nylon twine as good as a toothy edged knife?

 

Basically. The scratch pattern of an edge will impact its edge retention in different cutting tasks. In slicing tasks, a coarse edge is more aggressive and holds its edge longer, but the peaks of the micro-undulations in the edge are more prone to being rolled over in pushing cuts, and so they blunt faster when used for push-cutting, while highly polished edges will quickly lose slicing aggression because of how smooth they are, but will perform better and longer in push-cuts. It's kind of analogous to TPI with a saw. The direction of the scratch pattern matters, too, and can be considered as akin to the rake of a saw's teeth. You can see this very easily in cutting a piece of copy paper--use a coarse edge (with a clean apex) to slice against the slant of your scratch pattern (for most people this will be a drawing cut) and with it. When going against it, you'll be able to feel the "teeth" of the edge engage far more than when cutting in the other direction, which will feel comparatively smooth, but less rapidly penetrating (sort of like when starting a cut with a saw by using a few strokes opposite its cutting direction.)

It's actually really important knowledge with my scythe work because different vegetation and different mowing conditions require your edge to be tuned to different points along that spectrum to be maximizing your productivity. For instance, cutting fresh spring dandelions or other tender leafy growth, especially early in the morning when the dew is up, is best done with a finer edge and you can hang the blade more open to take a deeper swath, but during mid-day when the dew is off and dealing with waxy, thin grass varieties that like to "slip" off of an edge, a coarse edge and closed hang is needed to more aggressively bite and slice the stalks that would just fold under a polished edge that was even the tiniest bit shy of peak sharpness. You'd be honing every two strokes in those conditions using a fine stone.

 

Thinner edges have higher edge retention when it comes to enduring abrasive wear, but they're less able to withstand side-loads on the edge and so are more likely to dull by rolling/denting than thicker edges. Thicker edges have lower edge retention in resisting abrasive wear, but will resist blunting from torque a lot better. Interestingly, thinner geometries can often reduce strain on the region behind the edge because of their longer slope spreading out impact force over a longer distance/period.

As a general rule, cutting tools should be kept as thin as is consistent with requisite strength.

 

My statements were presuming holding all else equal to isolate the variables. The biggest issue with razors is mostly that they're too thin to survive that kind of work at their hardness range. You could probably use a wedge-ground straight razor to cut carpet without blowing the edge out on it, though of course it'd still ruin the edge for shaving with--the requirements for that are much more strict than for general-duty cutting tools!