Sloyd Knife Bevel angles for spoon carving

Time to take a few paragraphs to explain edge bevel angle and how I tune it create knives that excel in different situations and purposes.

It’s fairly simple really, my experience confirms that the bevel angle that your Mora 106 carving knifes comes with, that being a 28 degree bevel (14 degrees on each side) is generally the best balance of all important attributes.  Straying from this 28 is where you can create a knife that has a slightly different strength and purpose. 

Lets go down in angle first, to say 25 or 26 degrees.  This more acute, finer bevel is going to feel “sharper” or lower friction.  It’s going to cut across grain easier, so picture that cut around the front of the bowl of the spoon early on when things are still a little thick.  A low angle bevel is going to be longer, granted the blade thickness is maintained among other knives compared.  That long bevel is going to engage into a heavy cut and stay put.  That means early in the spoon carving process the lower angle bevels are great for removing heaps of wood fast.  Low friction, heavy cuts, chips are flying, everything is coming down to shape pretty quick!  Remember I said “feels sharper”, in reality this knife is probably less sharp pretty quickly after putting it to use.  The metals capability to hold a true edge at the lower angle is going to be slightly reduced compared to that same blade at say 30 degrees, that is just the nature of the material and the math.  But the fact that the overall wedge of the blade cross section is more acute means that as long your trying to remove a large slice of wood, this blade will feel low friction as long as the true edge is reasonably sharp. 

Here Emmet is executing what we often call the “band saw stage”. He’s carving the circumference of the spoon but keeping things thick enough to adjust other planes slowly as he goes. This cut right here is where a 26 angle shines, as he’s taking a substantial cut across grain at the front of the bowl. There is a lot of friction here and your hands will fatigue.

But lets take our “reasonably sharp”  low angle edge and try to attack that little fuzzy fiber spot in the turn around of the bowl to handle neck transition.  Weird, now this thing feels really dull!  I’m trying to finesse this edge through this tiny little blemish and it’s really not doing much for me.  Feels like one step forward, one step back.  A couple of times it even got a little hung up in the grain and bit of way more than I wanted it to, so I actually just took like 5 steps back.  Damn!

So in my opinion it’s time to switch to a 30 degree edge, or at least a 28 degree that’s in better shape, maybe one you have saved for just finish work.  I digress, I’ll stick with talking about the 30 degree first.  Roughing out a spoon with a 30 degree is a slog, it feels like running in boots as compared to sneakers.  The cross section of the 30 degree bevel is even more of a wedge that you’re trying to push through the fibers and the especially difficult cross grain fibers are where you’ll really feel the difference.  But this more obtuse wedge is better at two things.  It will hold it’s finest edge slightly better, and it intentionally slows you down when the going gets detailed.  It’s not going dive as deep or remove as much wood.  It will skim the surface better, take the a thin slice and keep you out trouble so you can clean up all the pesky spots.  Got some tiny micro chamfers to add to the edges of the bowl?  The 30 degree bevel will float through these high risk cuts where the 26 degree will dive in, rip off a huge chunk and laugh at you for being so bold.

Here Emmet is nearly finished and adding those tiny micro chamfers to all the edges. This is great time to use the 30 degree bevel knife. Here you’re not looking for speed or ease, you’re looking for control. The more obtuse bevel angle will ride higher, shave thinner, and avoid “overcooking” the cut and removing more wood than you hoped. Saving a knife for this work also means you have one knife that is far sharper and ready to really perfect things.

So there you have a roughing knife and finish knife, just by changing the bevel angle.  We’re talking about flat bevel here, no convexing or secondary bevel, that would change the formula completely and this entire conversation would be out the window.  The belly profile (refer to the last blog post), and the thickness of the blade and bevel will also play into the characteristic of the cut, but we’ll take these explanations one at a time.  I personally believe the low angle knives are only useful for experienced carvers with an eye to efficiency.  If you don’t understand grain flow around a spoon yet the 26 is just going to punish you and tear off huge chunks you weren’t ready for.  (Emmet is shaking his head now in protest)  What are you in a rush for?  You’re learning a craft, not trying to squeeze every spoon into 40 minutes to make profit margins work.  Get the 28 and maybe the 30 just to see, skip the 26.  But maybe it’s time to pick up the pace a bit, and lower the strain on the hands?  Ok, now you can try that 26. 

So now let’s bring it full circle all the way back to the 28 degree.  I wouldn’t be without a 28 degree, or actually a couple of them because I carve for a living (handles and sheaths, but yes I still have to carve to finish my products).  The 28 is the best balance of all cutting attributes if you’re not looking to create a tool kit with a massive number of specialized tools.   You can’t go wrong with 28, but you might be able to more right with one of the others.  That is kind of what like to offer, “more right”

And now because you might be wondering if any of this applies to hook knives, Yea it probably does, but I don’t go there.  I match the bevel designs and angles on my hook knives to the depths at which they are designed cut and hollow.  A open hook designed for flatter broader bowls has a bevel tuned to cut across and shallow rather than down into and then out like a hook fo carving scoops. That’s another blog post though

A few tools I use to measure to bevel angles. I would never bring a finished tool to the metal protractor for fear of nicking it. I use the metal one in the rough stages of sharpen as it’s the most acurate. The plastic coins are the least accurate, but offer a quick way to just see where a bevel might be at when you have no idea. I always bring that one to events so when people inevitably say “I wonder what my bevel is” I can tell then roughly what I think.

My trained eye can often guess a bevel angle at a quick glance. These two blades are the same thickness of 3mm. The 30 bevel on the left is visibly shorter than the 26 bevel on the right. Think about the angles and math quickly and it will make sense. That long bevel is one of the reasons Low angle knives take big bites, but are little tougher to control and steer. That big bevel is going to find a course and hold it, like a long set of downhill skis. The shorter bevel will steer in and out better like a short set of slalom skis.

Blade Curve Matters and we're talking about the straight knives this time....That's confusing isn't it?

I’m gonna nerd out on blade profile for a minute.  Actually while drafting this out as an Instagram post I decided to add a little blog section to my website so I can go in depth if I desire.  So here it is my first blog post -

I’ve been considering the impact profile curve or “belly” has on wood carving knife performance and here are my findings.  First off I’ll say I have two distinctly different ways in which I carve, that being green wood logs for spoons and kiln dried boards for tool handles and hook sheaths.  Overall I would say that the green wood approach is easier, not only because the wood is softer and more mellow, but because from a log I have more control over the way grain flows through my desired form.  I can skew the entire form within the log so that the knife is always gently crossing grain fibers and preventing the knife from getting stuck tracking down grain and tearing off huge chunks of wood.  There will be tricky spots, but I won’t have an entire spoon or project made up of all tricky spots.  Boards make it easier to use a drill jig to fit a blade, use handle shape templates and follow tighter standards when making lots of the same or similar knife handles. But I have no control over grain flow.  I have what I have in a 5/4” board (lumber talk for 1”) and the form needs to the fit into it.  No skewing across grain is allowed in many cases.  Since boards are usually sawed pretty straight down the tree you end up with a lot of pieces where the knife follows the grain too perfectly.  You know the challenge this poses if you have ever tried making a strong pair of chop sticks.  Everything is going great and suddenly “split!!!” You just lost half the chop stick in a grain tear out.  When ever possible I will chose a part of the board that gently crosses the grain and make my life easier, but it’s usually only a portion of each board that allows it. BTW, those are the handles that usually feature chevron patterns like the knife handle below.

This is a good example of what it means to skew across the grain. Too far and you’re going cross grained, which is really hard on the hands and knife, and makes items weaker. Gently crossing the grain is the sweet spot for carving fast and without tricky spots. Also hook handle are finished with a scraper to really unify the facets as one flat plane, cheating a bit ;)

So with these too distinctly different situations I have grown to appreciate two distinctly different knives.  For spoons I usually pick the low belly sloyd style, the straightest blades you see me regularly make, that feature just an ever so slight curve.  The straighter curve helps to lock in long planning cuts and the fine tips allows you to make successful cuts in tighter inside curves.  Spoons are curvy and you usually have more outside curves than inside curves, the only inside curve being the skinny neck, where you’ll likely rely on and need the thin tip to cleanly get you through.  Those long planing cuts progress easily as long as they are gently crossing the grain fibers not following them or . My knife handles are all fairly straight lines that follow the grain annoyingly close most of the time.  Here I find that the blade with a more dramatic belly or curve is able to negotiate in and out of those slight changes and prevent tear out situations of getting stuck in the grain.  When carving tools handle and sheaths all of my cuts are shorter.  Rarely can I engage at one end and follow through to the other.  The facets you see on the handles are the result of many small cuts, often changing directions many times along the length of the facet.  Attempting the bold long cuts I make on my spoons will certainly lead to disastrous tear out and failure to cleanly complete the project.  The bellied blade is so good at negotiating these small short cuts in and out of the grain fibers, entering and then cleanly exiting before encountering trouble. 

Left and Middle feature the increase in belly, while the Right side is a very low belly traditional sloyd knife shape. Left most has a “snubbed tip” to offer lots of tip strength, best if you want to use the knife in a large variety of situations, from simple whittling, to camp and shop chores. Middle Knife - by swaying the spine a bit you can keep the tip a little finer but still maintain the bigger curve to the cutting edge. This is my handle carving knife.

So hopefully that info informs you on what knife to grab for in what situation. Long and straight will excel in forms with well behaved and mapped out grain flow consisting of lots of nice curves, while a bellied blade will help you negotiate the tricky spots that follow the grain flow to closely. 

Next time your carving with your Mora 106 or similar style blade notice which section of the blade you rely on in what type of wood fiber scenario and cut.  Now imagine if you could exaggerate that feature to optimize it even further?  Or maybe place it differently in relationship to the handle? That’s what I hope to offer in my line of straight sloyd blades, the opportunity to really design knives that excel at completing your style of work. 

Alrighty, how did I do? I would not consider myself much of a writer, thanks for reading