Interesting Article on Micro-Bevels and Moras.... "Is your Mora too sharp?"

[HoosierQ]

I too have taken to putting a 30 degree inclusive microbevel on my Moras. I just use the Sharpmaker, about 50 passes each side, each grit, and then strop with the green compound. Still scary sharp but more durable.

 

[RLANG]

The practical utility of adding a micro bevel to a zero edge also demonstrates, indirectly, the benefits of stropping. As was mentioned, stropping transforms a flat edge into a semi convex edge which is stronger. If your fine edge deforms, and you have difficulty in producing an even precise micro bevel, try stropping with black and white compounds. The black shapes the edge, the white polishes.

 

[hardheart]

Speaking to the amount of friction generated by the backbevel, why would that be any greater than a flat grind 20 degree edge with a 30 degree primary bevel

Because there's no such thing as a 20 inclusive degree flat grind. A ten degree per side bevel on a 1/8" thick blade is going to go about 5/16", a 1/4" beast will have a 5/8" wide bevel. I don't personally know of any quarter inch blades that are only a bit over half an inch tall. The scandi grind is a primary bevel that is the same as an edge bevel applied with other grinds. The increased friction is from the fact that the entirety of the bevel is that much more obtuse. When used for a planing action on wood, it isn't a problem. It increases the human hand's ability to control depth of cut by giving that nice wide reference bevel. But when trying to cut through something, it translates a much greater amount of the applied force to the plane perpendicular to bevel. The further the bevel deviates from 0 degrees, the more wedging force and less cutting force.

And a steel that can't handle 11 degrees per side isn't so hot. Some competition cutters chop wood and golf balls with single digit included angles on their blades. It doesn't matter if it's scandi, flat, or convex ground - the first hundredth of a millimeter from the cutting edge is exactly the same if the angle is the same, and that is where sharpness exists and is lost with use.

 

[HeavyHanded]

After posting my last response I turned my Mora over in my hands and came to this realization - 20 degrees inclusive with a flat grind is a hatchet.

That said, while I don't really like my Moras, they are very good utility cutters.

None of the cheaper production steels are going to hold up with single digit inclusive bevels. At 16 degrees (approx) or less, most will visibly deflect if pressed laterally against a ball point pen.

 

[pwet]

It's good steel hardened to around 60. My little opinel is at 20 and it's edge lasts forever and it's a softer steel.

you're talking about stainless opinels right ? because the carbon ones are over 60 hrc from my estimation. i've seen one tested at 62 or 65 iirc but can't find the source right now.

 

[iammark]

I too have taken to putting a 30 degree inclusive microbevel on my Moras. I just use the Sharpmaker, about 50 passes each side, each grit, and then strop with the green compound. Still scary sharp but more durable.

This is good to know------thanks! (even though that's what I'd already done anyway.........:S)

 

[iammark]

This is good to know------thanks! (even though that's what I'd already done anyway.........:S)

I take that back!!! The 30 degree is the Sharpmaker 'backbevel angle'-------I used the regular 40 degree edge angle!! :S I'm going to re-hone at the 30 degree 'Sharpmaker backbevel angle'. I'm missing out on some Mora sharpness!!

 

[Jakeboy]

I have a few Scandi grind knives and noticed that a big factor in cutting ability isn't the existence (or lack) of a micro bevel, but the thickness of the blade itself. I have 5 Moras and they cut through just about everything with great ease. I also have a Helle Tiaga whose blade is around .120" thick and it doesn't slice through cardboard or leather as well as the Moras. The Tiaga is razor sharp, as are the Moras.

Does the blade thickness have a bigger impact on cutting ability than the type of grind, other factors being equal?

 

[pwet]

on a scandi obviously. on a ffg way less.

 

[Thomas Linton]

The Sloyd wood-carving knife classically had a secondary, convex bevel due to free-hand sharpening by the wood carver. Perhaps no one had told them, over the generations. 0___0

 

[Thomas Linton]

you're talking about stainless opinels right ? because the carbon ones are over 60 hrc from my estimation. i've seen one tested at 62 or 65 iirc but can't find the source right now.

Perhaps things have changed. I have two 20+ year-old Opinals in carbon steel, purchased months apart from different vendors, and they are quite soft.

 

[Obsessed with Edges]

Perhaps things have changed. I have two 20+ year-old Opinals in carbon steel, purchased months apart from different vendors, and they are quite soft.

That mirrors my limited experience with my 'carbone' No. 08, purchased within the last year. I don't know if I'd call it 'soft' per se, but it doesn't seem particularly harder than any other inexpensive carbon-bladed folder. I bought mine along with a stainless version, and sanded down both blades to a somewhat thinner zero edge. I noticed, when sharpening both of them, the carbon model tended to round off a little too easily at the the edge, if I pressed a little too hard on the sandpaper or strop. I also had to repair a couple of dings in the edge on that one, produced when I inadvertently bumped the edge against some binder clips holding my sandpaper. These were dents/rolls in the thin edge, which I think would've otherwise chipped at hardness levels above 60 RC. The stainless version (Sandvik 12C27Mod) held up better, under the same treatment. Sandvik specs that steel up to 59 HRC, so I think the carbon bladed model was more 'typical' in hardness for such a blade, maybe mid-to-high 50s RC.