What's the lowest functionable angle by steel type?

[trailhunter]

Trying to figure out what's the lowest angle one can go based on different types of steel? Couldn't find a good reference on this (maybe because its subjective?)

 

[Wowbagger]

You mean for safety razor blades ?

For a regular EDC or kitchen knife grind it very thin behind the edge and very shallow angle.
Use it for the intended work.
If it fails, gets dinged up (to some this looks like "chipping" but often with magnification it is the edge getting dinged up) . . . sharpen to a degree per side wider angle and use again. It almost depends more on the material being cut (and the heat treat) than it does the steel being used.

Have you seen the Carter Cutlery YouTube about edge geometry that I post too often ? If you haven't I can imbed it here if you like. Totally right on info. I don't agree with all things Carter but that short vid is the bee's knees, the cats meow, the . . .

 

[trailhunter]

You mean for safety razor blades ?

For a regular EDC or kitchen knife grind it very thin behind the edge and very shallow angle.
Use it for the intended work.
If it fails, gets dinged up (to some this looks like "chipping" but often with magnification it is the edge getting dinged up) . . . sharpen to a degree per side wider angle and use again. It almost depends more on the material being cut (and the heat treat) than it does the steel being used.

Have you seen the Carter Cutlery YouTube about edge geometry that I post too often ? If you haven't I can imbed it here if you like. Totally right on info. I don't agree with all things Carter but that short vid is the bee's knees, the cats meow, the . . .

Watching now. Thanks for the tip!

 

[Wowbagger]

did you watch this one ? It is the one I am talking about.

 

[Ourorboros]

Type of steel, heat treatment, annealing to make the blade tougher, grind, profile
What you are trying to do, how you do it, your taste for keen edge vs edge holding, your taste in what happens at failure - chipping or rolling

A few of the variables you contend with. Even with the same knife, two skilled people will not necessarily choose the same angle. Personally I'll put on a more acute angle at the cost of edge holding on many of my knives. OTOH I don't mind sharpening and also have a lot of knives, aka a replacement I can grab for now.

 

[wade7575]

For a good edge that won't be chippy if you do not abuse it is 15 degree's on most Spyderco knives for example,you also have to take into account blade thickness for example a Hinderer XM-18 I will not go past 20 degree's per side there is no point trying to take it down any lower as the blade is to thick and you won't feel any more sharpness when cutting.

I learned that lesson the hard way when I first started sharpening and you try and take a Hinderer down to 15 or less per side but it still won't be a great slicer because the blade is thicker it's better suited to a hard use knife where as Spyderco's make better slicer's for cutting box's and package's open and you can still cut rope and stuff with the over even clean a fish if need be.

It's all about the blade and how thick it is as to how low of angle you can go and you also have to look at the steel that was used in the knife and the heat treating as not all heat treatment's equal when comparing the same 2 steels.I have a Japanese chef knife that a Master of working with Shirogami 1 steel and heat treating it and his knives n that steel are 65 RC hardness and the edge does not get chippy where other makers struggle to get it to 63 to 64 without making the edge chippy.

 

[mycough]

A gross over simplification but lower alloy steels seem to support the lower angle edges, some of the super steels get pretty schizo below 15 degrees.

Russ

 

[HeavyHanded]

Super steels can support a thinner primary grind, generally speaking, but not necessarily at the edge.

Lower than about 24° lateral stability begins to take a dump becoming more pronounced as you go, though at the edge it might still cut well if not abused. Most steels can tolerate 26° or so with no real issues tho some might do better with a small microbevel to bring the actual edge up closer to 30. Better quality steels with good HT can be run pretty thin - to where the edge deflects when pressed against a pen. But...lateral stability will be a concern.

 

[Obsessed with Edges]

Super steels can support a thinner primary grind, generally speaking, but not necessarily at the edge.

Lower than about 24° lateral stability begins to take a dump becoming more pronounced as you go, though at the edge it might still cut well if not abused. Most steels can tolerate 26° or so with no real issues tho some might do better with a small microbevel to bring the actual edge up closer to 30. Better quality steels with good HT can be run pretty thin - to where the edge deflects when pressed against a pen. But...lateral stability will be a concern.

A gross over simplification but lower alloy steels seem to support the lower angle edges, some of the super steels get pretty schizo below 15 degrees.

Russ

Agree with both of the above. Every knife I use is somewhere in what I think of as the 'safe zone' for good edge geometry, which is roughly 25° - 30° inclusive. This includes anything from 1095, 420HC up to D2, S30V, S90V, at hardness values ranging from mid-50s up to 60-ish HRC.

The only exception I've found, was with a ZDP-189 blade at low-mid 60s HRC that I'd thinned to about 30° inclusive, which turned out to be a little too thin for it's own good. Immediately upon finishing that thinning job, while stropping the blade, the pointy tip dug into the strop and snapped about 2mm of it off. It's a little too hard, brittle & fragile to be durable at 30°, and I'm reluctant to use it much at all, for that reason.

Low-alloy stainless, such as found in inexpensive kitchen knives, is ironically probably the easiest to live with at very thin edge angles. It's true, such steels will roll easily at very thin geometry. But the same ductility that allows it to roll that easily is also what will allow the edge to be realigned back into shape on a polished steel honing rod, with little or no additional repair or regrinding of the edge. Such blades can therefore go a long time between any significant resharpening jobs, as used for the relatively low-wear tasks they perform in the kitchen.

 

[Jamesh Bond]

Cool thread.

 

[bucketstove]

Hi,
Yup, searching for knife info can be difficult

Metallurgist Dr. Roman Landes says, if carbide volume is 0.5-5%, to both take and hold a high polished sharpness, you need 8-12 degrees per side.

Metallurgist Dr. Roman Landes says, if carbide volume is 5-15%, to both take and hold a high polished sharpness, you need 12-20 degrees per side.

Metallurgist Dr. Roman Landes says, if carbide volume is greater than 15%, to both take and hold a high polished sharpness, you need 20-30 degrees per side.


From Romans book Messerklingen und Stahl , marthinus quotes Romans original post with updated pdf link and other good ones, I embedded image of pdf below,
cpm-m4-at-low-angles-my-experience-recently.1086828/page-2#post-12414439
roman-landes-knife-edge-diagram-angles-carbides-schneiden.png
Patent US5830287 - Wear resistant, powder metallurgy cold work tool steel articles having high ... carbide volume chart


Spyderco Sal Glesser says that he sharpens all of his knives at 15 degrees, as all of Spyderco's steels can handle it. So if you have problems at 15 degrees you should send the knife to Spyderco as defective with a chipping problem.


consider that under 15 dps edge can chop bones And 12 dps edge can still shaves/whittles beard hair after 1000 slices of hardwood ( yes a 1000 slices of hardwood )
This utility razor blade pictured here has ~10dps edge/0.017in(431.8micron), increase that to 15-25dps and try cutting up that same chicken bone, (all the other pictured knives all sharpened to 30-inclusive)

When [url=https://www.youtube.com/watch?v=JSle2YMY-18]Joe Calton mentions 0.020" thick for chopping bone, that is roughly comparable to the green blade in the diagram above. 0.020"

[/URL]


Compare to this image that howto measure angles thickness with calipers

Sharpening method or blade steel? Its always the geometry.

Geometry defines the limits of cutting performance, steel defines the limits of functional geometry which are influenced strongly by user skill level and physical ability.
Geometry and proper sharpening vs steel quality



To fine tune a knife, without knowing much about the numbers of the thicknesses or angles, if making a 1000 slices at a time doesnt damage the edge like this (roll/reflection or chip), keep lowering the angle
Normark EKA 12C27 : optimal edge geometry for slicing hardwoods (norton economy fine edge) - CliffStamp

So the way I think about edge angles and thickness,
compare your edges with your fingers/eyes to utility knife razor blade
don't need to know actual thickness numbers of your edge,
if your utility knife blades dont say how thick its easy to measure with simple centimeter/mm ruler, then compare to this list, and decide go up or go down

• 4 to 6 dps (8-12 inclusive) -<0.005", light use knives, paper and cardboard, light ropes, knot free woods
• 8 to 10 dps (16-20 inclusive) -<0.005"-0.015", moder push cuts on woods, thicker plastic, heavy ropes
• 12 to 14 dps (22-28 inclusive) -<0.015"-0.025", hard push cuts on very knotty woods, bones, etc.
• 12 to 14 dps (22-28 inclusive) ->0.025" dps, chopping blades
• 0.025"/15 dps (30 inclusive) = 0.635 millimeters / 15 dps edge overbuilt , cutting into or contacting against very hard materials like rock, metals and such. It is over built for cutting but well built for durability in extremes/utility.
• 0.025"/15 dps (30 inclusive) = 0.635 millimeters / 15 dps edge overbuilt , you could chisel cut through nails and such without issues , $1 one dollar knives or $5
• 0.035"/20 dps (40 inclusive) = 0.889 mm 20 dps beyond overbuilt , $1 one dollar knives or $5
• 0.045"/25 dps (50 inclusive) = 1.143 millimeters /25 dps sillybuilt
• 25 dps and 30dps (50-60 inclusive) and higher are angles for metal cutting cold chisels or splitting wedges or a table knife

Its easy to see the truthfullness of this list, simply
take a box of utility knife razor blades and sharpen to see how low you can go.
Explode your mind through first hand experience not merely mind exploding videos, spyderco delica/pacific salt...Extreme Regrind , ~6DPS with 10dps microbevel, no damage in 50 slices into pine, hardwood flooring and plywood the edge eventually gets damaged while cutting metal (steel food can)

Leonard Lee's The Complete Guide to Sharpening recommends felling axe edge angles as low as 10-12 dps. Granted, he does qualify it by saying clean (knot free) green wood, but still. In any case, challenge accepted. We'll see what happens.

Here they says 25 degrees (12.5 degrees per side), An Ax to Grind: A Practical Ax Manual - 99232823 - FS Publications - Publications - Recreational Trails - Environment - FHWA

Most axes have a 30-40 degree angle at the end of the bit and a 15-20 degree angle about ½” from the cutting edge.

gransforsbruk

1 listed for frozen wood is 80 degrees or 40 degrees per side (cold chisel, skew chisel)
2 listed for softwood is HIGH angle at 42 degress or 21 dps
3 listed for carving is is 25 degress or 12.5 dps

 

[trailhunter]

Hi,
Yup, searching for knife info can be difficult

Metallurgist Dr. Roman Landes says, if carbide volume is 0.5-5%, to both take and hold a high polished sharpness, you need 8-12 degrees per side.

Metallurgist Dr. Roman Landes says, if carbide volume is 5-15%, to both take and hold a high polished sharpness, you need 12-20 degrees per side.

Metallurgist Dr. Roman Landes says, if carbide volume is greater than 15%, to both take and hold a high polished sharpness, you need 20-30 degrees per side.


From Romans book Messerklingen und Stahl , marthinus quotes Romans original post with updated pdf link and other good ones, I embedded image of pdf below,
cpm-m4-at-low-angles-my-experience-recently.1086828/page-2#post-12414439
roman-landes-knife-edge-diagram-angles-carbides-schneiden.png
Patent US5830287 - Wear resistant, powder metallurgy cold work tool steel articles having high ... carbide volume chart


Spyderco Sal Glesser says that he sharpens all of his knives at 15 degrees, as all of Spyderco's steels can handle it. So if you have problems at 15 degrees you should send the knife to Spyderco as defective with a chipping problem.


consider that under 15 dps edge can chop bones And 12 dps edge can still shaves/whittles beard hair after 1000 slices of hardwood ( yes a 1000 slices of hardwood )
This utility razor blade pictured here has ~10dps edge/0.017in(431.8micron), increase that to 15-25dps and try cutting up that same chicken bone, (all the other pictured knives all sharpened to 30-inclusive)

When Joe Calton mentions 0.020" thick for chopping bone, that is roughly comparable to the green blade in the diagram above. 0.020"



Compare to this image that howto measure angles thickness with calipers

Sharpening method or blade steel? Its always the geometry.

Geometry defines the limits of cutting performance, steel defines the limits of functional geometry which are influenced strongly by user skill level and physical ability.
Geometry and proper sharpening vs steel quality



To fine tune a knife, without knowing much about the numbers of the thicknesses or angles, if making a 1000 slices at a time doesnt damage the edge like this (roll/reflection or chip), keep lowering the angle
Normark EKA 12C27 : optimal edge geometry for slicing hardwoods (norton economy fine edge) - CliffStamp

So the way I think about edge angles and thickness,
compare your edges with your fingers/eyes to utility knife razor blade
don't need to know actual thickness numbers of your edge,
if your utility knife blades dont say how thick its easy to measure with simple centimeter/mm ruler, then compare to this list, and decide go up or go down

• 4 to 6 dps (8-12 inclusive) -<0.005", light use knives, paper and cardboard, light ropes, knot free woods
• 8 to 10 dps (16-20 inclusive) -<0.005"-0.015", moder push cuts on woods, thicker plastic, heavy ropes
• 12 to 14 dps (22-28 inclusive) -<0.015"-0.025", hard push cuts on very knotty woods, bones, etc.
• 12 to 14 dps (22-28 inclusive) ->0.025" dps, chopping blades
• 0.025"/15 dps (30 inclusive) = 0.635 millimeters / 15 dps edge overbuilt , cutting into or contacting against very hard materials like rock, metals and such. It is over built for cutting but well built for durability in extremes/utility.
• 0.025"/15 dps (30 inclusive) = 0.635 millimeters / 15 dps edge overbuilt , you could chisel cut through nails and such without issues , $1 one dollar knives or $5
• 0.035"/20 dps (40 inclusive) = 0.889 mm 20 dps beyond overbuilt , $1 one dollar knives or $5
• 0.045"/25 dps (50 inclusive) = 1.143 millimeters /25 dps sillybuilt
• 25 dps and 30dps (50-60 inclusive) and higher are angles for metal cutting cold chisels or splitting wedges or a table knife

Its easy to see the truthfullness of this list, simply
take a box of utility knife razor blades and sharpen to see how low you can go.
Explode your mind through first hand experience not merely mind exploding videos, spyderco delica/pacific salt...Extreme Regrind , ~6DPS with 10dps microbevel, no damage in 50 slices into pine, hardwood flooring and plywood the edge eventually gets damaged while cutting metal (steel food can)

Leonard Lee's The Complete Guide to Sharpening recommends felling axe edge angles as low as 10-12 dps. Granted, he does qualify it by saying clean (knot free) green wood, but still. In any case, challenge accepted. We'll see what happens.

Here they says 25 degrees (12.5 degrees per side), An Ax to Grind: A Practical Ax Manual - 99232823 - FS Publications - Publications - Recreational Trails - Environment - FHWA

Most axes have a 30-40 degree angle at the end of the bit and a 15-20 degree angle about ½” from the cutting edge.

gransforsbruk

1 listed for frozen wood is 80 degrees or 40 degrees per side (cold chisel, skew chisel)
2 listed for softwood is HIGH angle at 42 degress or 21 dps
3 listed for carving is is 25 degress or 12.5 dps

Mindblown. Reading this in its entirety.

I've been ultra conservative at 40 degrees inclusive irrespective of steel type. But as I start venturing out to find the truth. Everyone who has participated in this thread opened my mind that I can start exploring significantly thinner angles

 

[trailhunter]

Is it common practice to reprofile brand new knives right out the box or are stock angles normally used and reprofiled thereafter?

 

[trailhunter]

For a good edge that won't be chippy if you do not abuse it is 15 degree's on most Spyderco knives for example,you also have to take into account blade thickness for example a Hinderer XM-18 I will not go past 20 degree's per side there is no point trying to take it down any lower as the blade is to thick and you won't feel any more sharpness when cutting.

I learned that lesson the hard way when I first started sharpening and you try and take a Hinderer down to 15 or less per side but it still won't be a great slicer because the blade is thicker it's better suited to a hard use knife where as Spyderco's make better slicer's for cutting box's and package's open and you can still cut rope and stuff with the over even clean a fish if need be.

It's all about the blade and how thick it is as to how low of angle you can go and you also have to look at the steel that was used in the knife and the heat treating as not all heat treatment's equal when comparing the same 2 steels.I have a Japanese chef knife that a Master of working with Shirogami 1 steel and heat treating it and his knives n that steel are 65 RC hardness and the edge does not get chippy where other makers struggle to get it to 63 to 64 without making the edge chippy.

Makes sense so if it's too thick, you're angle would be mitigated by the friction of the width of blade. I haven't thought about this until mentioned by you and a few others here. I'll need to take this into consideration for my next purchase.

 

[HeavyHanded]

Is it common practice to reprofile brand new knives right out the box or are stock angles normally used and reprofiled thereafter?

I'll beat em up but once they lose a step they're going to be thinned, maybe even a primary regrind.

I can count on one hand the number of factory edges that were of solid quality out of the box...being persnickety about it.

 

[wade7575]

If you want a knife that's a great slicer Spyderco's are great if you ask me and I sharpen all mine 15 degree's per-side and that's what they claim at the factory,I find with Spyderco's that they seem to be sharpened at 15 degree's per-side but they have a smaller bevel then what a guided system or free hand sharpener would put on them I think it's just the way they put the edge on at the factory.

 

[Dangerously]

Is it common practice to reprofile brand new knives right out the box or are stock angles normally used and reprofiled thereafter?

I reprofile right out of the box. There’s nothing worse than having a shiny new knife kick the others out of your pocket, only to cut like crap. If you’re used to a 10 dps edge for your everyday tasks, you notice the extra force required to push a 20 dps edge through the same material.

 

[Obsessed with Edges]

Is it common practice to reprofile brand new knives right out the box or are stock angles normally used and reprofiled thereafter?

I'm in the habit of thinning/reprofiling almost every newly-acquired knife, unless I get lucky and find it's already close to where I want it at 30° inclusive or lower. Even then, I tend to take them a bit more acute with each resharpening, even if it's not a full reprofile job. On almost every new knife I've found, the apex itself can always be made better, from what I've seen. So many factory edges come with an apex that's obviously short of full completion, or rounded off & overpolished from the factory de-burring step. So they all get some work one way or another, before they go in my pocket.

I've become spoiled on how edges cut at ~ 25° inclusive or close to that. So, I'm not willing anymore to use anything much above 30° inclusive, until it's completely reworked. And 40°+ edges, I don't even want to look at them, much less use them, until they've been redone. Those ones tend to sit in a drawer, out of sight & mind, until I'm sufficiently motivated to fix 'em right.

 

[EdgePal]

Today we have two different types of living and that have forced our knifes and edges fo develop in two different directions. We still have the traditional way to use knifes and other edged tools - but now we also have city living developing of edges.

Traditionalist work in fresch wet materials as fresch wood, they skin games, butcher fresch meat, butcher fish and slice leather - end they use thinner blades and edges (and less force) then city people do. (I am a traditionalist and my chopper have a 26 degree total slightly convex edge).

City people chop, cut and slice harder materials that where edges more as dry hard wood,mcarsboard,mars plastic, soft plastic, paper, nylon, rubber, strings and other similar materials. Those materials needs steeper angles to hold.

Traditionalist knifes are just tools that must work. City people by often knifes that are fancy and good looking - and functionallity comes in second, and third place.

For example, city people often talk about "surviving knifes" and how they must hold for abusive use, they shall hold dor batoning, bending, be used as spears and so on. Traditionals take care about their knifes - and in. Survival situation they would never batoon or bend with a knife and they will never even think to throw a knife or use it as a spear head... They use their knife to make tools thay can, if they need, use hard - and if the tool broke they use their knife ro make a new tool. In a survival situation traditionalists take extream care about their knife becouse their life perhaps depends on that the knife works for them.

So, my point is that when we diacuss edges and edge angles - we must know where the knife shall be used and to what, shall it chop, cut and slice tradtional materials or hard city materials.

What I se today is that city people use their city knifes outdoors with high force and powerful chopping and hard batooning to get firewood - when I use my foot and stamp of firewood in smaller peices...

It is today two very different ways of using knifes. If I shall be hard I can describe it in a traditional soft way that work with the material and a romantik hard way that work against the material and where force are used, that is also the differance between a 40 degree city edge and a 20 degree traditional edge...

Traditionals never chop with a knife. If they need to chop they use a chopper or an axe.

Now, i describe Scandinavia today. I think that the situation is the same all over the industrial world today when 90 % of the population lives in citys and where old traditional knife knowledge are forgotten.

On forums, my impression is that more then 99% of the members lives in citys - so what people often discuss is how city knifes shall be used outdoors - ans how good, or bad, they work...from city people point of Wiew...

Please dont understand me wrong here. Knifes have allways developt out of needs and from use. That is why we have so many different designs of knifes in the world. City people shall of cause design their knifes, and edges, from what they need to have so that their knifes can be used in city materials.

But city knifes for city materials do not work so good outdoors in softer often wet materials.