30 or 40 degrees?

M

MacTech

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Jan 7, 2006
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I love to keep my knives as sharp as humanly possible, if they don't at the very least pop hairs, they're dull...

Generally speaking, I try to keep all my knives at 30 degrees inclusive on my Sharpmaker, anything with a thin flat or hollow-ground blade gets the 30 degree setting

I know that the 30 degree setting is less durable than the 40, and will require more frequent touch-ups, I'm okay with that, but I'm wondering if I'm being a tad obsessive here, especially with my traditionals, would they be better suited to the more durable, but still plenty sharp, 40 degree setting?

the following knives I sharpen at 30 due to thin bladestock and thin grinds and they seem to work quite well at this setting, decent edge retention and durability;
Opinel No. 8
all my SAKs
Case SS red bone Peanut
Case CV Yeller Trapper
the main blade on my SS Case red bone pocket worn Medium Stockman
the main blade on my Buck 303
Buck 110
Buck 112

The following knives I'm working down to 30, and are fighting me a bit and I'm getting frustrated
the sheepfoot and spey blades on both my Case SS Stockman and Buck 303, the Buck's spey and sheepfoot are especially frustrating, they do seem to respond well to the 40 degree setting though
Boker Whittler, the edges on all three blades are *almost* to the way I like them, but I just can't seem to push them to the Atom-Splitting level of sharpness I covet

for the above knives, the secondary blades on the Buck and the Case, and all the blades on the Boker, should I just forget the whole 30-degree Atom-Splitting sharpness and just be happy with a nice Scary 40 degree angle?

part of my reasoning for the 30 degree setting is since these classics generally have thin bladestock, they would be most effective with a 30 degree setting, and it seems to be a waste to put a more obtuse 40 degree setting on them

I'm still learning to freehand, using an old Schrade tiny stockman, but I'm not skilled enough to risk my nice blades freehand, *yet*

what say the experts? are some of these knives just better suited to 40 degrees, the Buck 303 seems to have the thickest grinds and bladestock of the slipjoint group, so I think it'd respond better to a good solid 40, but the Boker, geez, that one really deserves a 30, it's just fighting me, the main blade is *almost* there, maybe a little more time is all that's needed
 
A 30 degree angle is pretty thick for me. I naturally freehand at about 20 inclusive, and save 30 for the blades that get abused. You'll see a decent performance drop if you went to 40, though that is one of the standard angles.
 
Don't get too hung up on angles, rather than a practical every day using edge.

I can't really tell you what angle I use, as I've always sharpened free hand and went with something close to the factory angle. I mark the edge with a dry erase marker, lay the blade on the hone surface and hone in small cirlcles starting at the kick and going to the tip. Flip over and do the other side. If you've done it right, there's a nice shiney even edge in the right place and the right width. The marker lets you see if you're using too steep or too shallow and angle. After you get used to doing this, you just do it by feel, and don't need the marker.

I don't get too obsessed over whittling hair sharpness. If it gets sharp enough in a few minutes to shave a little hair off my arm or cut easy through twine or newsprint, I'm happy. I don't want too fine an edge that the first time I have to break down a dirty cardboard box for trash, or a slice open a gritty bag of top soil, and get sad because the nice edge I worked hard to get, just got wrecked. For many years now, I've went with a good sharp edge, but not surgical level. I strop the knife more often than sharpen. I just use the back of my belt where ever I happen to be. If it does get a little dull out someplace, then I use the cut down Eze-lap model L I keep in my wallet to touch up the edge. Takes a minute or two once you get used to it. For many years now, the cut down little Eze-lap has been my only sharpening system. That, and the back of my belt. I like to keep it smple and always with me. Field portable one might say.

Depending on the thickness of the blade, shape of the blade, material of the blade, and intended use of the blade, the angle may slightly change. It's not a fixed science. In some cases, it's not going to make a difference if it's 28 degrees or 32 degrees, or even 35 to 40 degrees. One thing to keep in mind, when you walk out the front door in the morning, you can't ever tell what you're going to run into. If there is some little, or big emergency durring the day, your knife may have to be pushed a little hard. I'd rather have the edge a little more toward the plus side of an angle than the shallow side. It's still going to open that plastic blister pack, open your mail, or cut that twine for the garden, but it will also stand up to a little more unexected punishment.

I think the best lesson I ever had in knife sharpening was from a proffesional trapper. This old guy Bill is an old timer up in Frederick county, and he traps all manner of creatures and hires out as a guide in hunting season. He is in high demand and you have to get him by summer or not at all. His knife is an old beat up Case sodbuster. One day he joins us at our Friday morning breakfast, and just before he leaves to go meet a client, he checks his knife, then turns over an empty coffee mug and uses the unglazed ring on the bottom to touch up his knife. A minute or two later he feels the edge with his thumb, smiles, and says "That's good enough!" and takes his leave of us.

He couldn't tell you what angle he was using if you put a gun to his head. But it felt right to him, and his knife was sharp. In the end, that's all that matters.
 
At some point you have separate sharpness and cutting ability.

A knife with a really low angel that is only barely hair scraping sharp, will most of the time out cut a hair popping sharp knife with a wide angel.

If you want your knife to cut well, you should go with the low angel ( maybe even less ).

If you want to shave with the knife then low is better to.

If you use your knife hard and often gets deep nicks and dings in your edge, a wider edge will be better.

In a sentence "If your knife turns dull with out being damage thin is good, if your knife turns dull with the edge being damage then wide is better."
 
Sword and Shield said:
A 30 degree angle is pretty thick for me. I naturally freehand at about 20 inclusive, and save 30 for the blades that get abused. You'll see a decent performance drop if you went to 40, though that is one of the standard angles.
Click to expand...

Yup, S&S has got it. This is exactly right.. Well, for me anyway. I've never used 40 degrees, ever. I freehand with a myriad of stones/hones at 20-22 on every working knife I own and find dry stropping with leather in between sharpening does yeoman's work when a touch up is required.


Anthony
 
First off, if you are taking the factory angles down to 30 with only the Sharpmaker...STOP! It works too slowly and you are doing more work than you need to. Get yourself a carborundum/Sic stone or even a coarse India, the diamond stones work as well but are pricey. You can either freehand the edge down to a lower angle and then put a microbevel on with the Sharpmaker, or you can lean the stone against the rods and use it like a very coarse triangle rod. If you freehand on the coarse stone don't worry about getting the edge perfect, all you need to do is work up a burr on both sides of the knife at a lower angle than you will be finishing with, the Sharpmaker will put the final touches on the edge. A coarse stone will go a long way in keeping you from overworking and/or getting frustrated.

Microbevels are your friends, they give you the performance of a lower angle (eg. 20,25,30) but give you better edge stability and offer increased speed and ease of sharpening. If you freehand sharpen only, it is rather difficult to maintain one even and wide bevel, but if you raise the angle near the edge and give it only a few strokes per side, then it is easier then using the sharpmaker once you do it a couple times.

I agree with everything Jackknife said about not being so particular about your edges, if it makes you happy spending all that time and effort on something that will dull with use then take as much time as you like getting it perfect. While the traditional knives we like to carry are thin and cut well, the steel used is often of the softer variety and will dull pretty quickly, I don't mind because they are so easy to sharpen and stay plenty sharp until I can touch the edge up, but they aren't super steels by any means. I know I used to be the same way about sharpness, all my edges would be on par with light sabers until I really started to use my knives more in the real world. A good sharp edge off a medium or fine Arkansas and an occasional light strop is all I use these days, works great in actual use and only takes me a few seconds to get. I don't worry too much about dulling a knife from use anymore because I know I can put another edge on just like it in no time.

To answer your question, I would use about a 20-30 back bevel with a very thin 40 degree microbevel.
 
I keen up everything I have at the 30 degree angle on the SM. I've never had any problems, but if I get something that I feel is not heat treated properly it goes bye bye!
 
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well i am fairly new to sharpening ( ok brand new, i got a sharpmaker on wednesday)

but i have decided after a few non scientific tests, that i liek a 30* back bevel iwht a 40* cutting edge.

this profile slices well, push cuts printer paper, slices newsprint and whittles hair for me, and thats what i like.
 
Brian,I totally agree w/ everything you wrote.Well said,my friend.
I free hand sharpen mine well once a month on Norton fine India stones down to X fine Hard Arkansas stones and strop.If I hit a staple while cutting a box,I keep a telescoping diamond pen sharpener close by to touch it up and strop on the top of my boot and I'm set to go.Angles,on my folders 15-16* and sheath/field knives 19-20*.Enjoy your knife.DM
 
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