Zero grind question

[REK Knives]

Zero grind mean no secondary bevel at the very edge.

You can have full flat zero grind, convex zero grind, saber with zero grind or in another name "scandi" or whatever grind that you don't put the secondary edge bevel on it can be called as zero grind.

There is nothing magical about zero grind... It will be sharper because its generally has thinner geometry at the very edge but it will be much more fragile to.
And once its dulled and you will need to sharpen the whole primary bevel to maintain the zero grind unless you will need edge bevel soon.

^^ Good post.

________________________

Changing the grind is all about dialing in a knife to the way the knife is used. Imho, production knives are set up (most of the time) for the hardest uses the knife will see because the manufacturer knows that there will be all sorts of people buying their knives and wants to minimize warranty issues.

But the problem with this is that angles are wide (often times 25+ dps, even on many customs I've come across!!), and the grinds are thick - both of which lead to them being poor cutters, which is the point that most of us buy knives in the first place: to cut stuff lol.

To clear up a little confusion... here is a chart (note that the term 'bevel' can also equate to 'grind' so 'primary bevel' also means 'primary grind':

A zero grind simply means that there is no secondary bevel. A true scandi grind has no secondary bevel and is therefore considered a zero grind. Zero grinds can be chisel ground (only on one side) or v ground (on both sides) and can be done in flat, convex, or even hollow I suppose (although the last would be very fragile).

What our goal is, as users, is to dial in our knives to OUR uses... i.e. the heaviest use that our knife will likely see. The goal is to make the knife as thin as possible for our use without compromising strength (the ability to bend back and hold it's original shape under use) or toughness (the ability to dent instead of fracturing). This will yield a knife that cuts WAY better than stock yet is still plenty durable for all of our needs. A side benefit to thinning out the grind is also that it makes touch ups a TON easier =)

Emersons work well with zero grinds because of the stock thickness and relative low grind heights. You wouldn't want to take a ffg spyderco to a zero grind without severe fragility issues. So if it will mainly be a slicer, I would totally zero grind an emerson. If it will be twisting under zip ties and seeing heavier use I would recommend a secondary bevel of .005-.010" thick depending on the heaviest use. All this being said I rarely recommend going over 15 dps, unless and ONLY with a microbevel (for apex stability). But anything more obtuse than 15 for a secondary (for the most part) is not maximizing performance that you COULD have without compromising any blade integrity.

Please take what I say with a grain of salt because I have only ever zero ground emersons, never actually carried and used a zero ground emerson so that's why I err on the side of caution when making recommendations.

Here's a few pics of some zero grinds for thought... The 7's are perfect for a zero due to the super short grind height.

But most of the time I recommend leaving a small secondary bevel like this (it's small but there and adds plenty of stability to the apex) It is also popular to convert to a V edge at the same time =)

 

[Lycosa]

Excellent post, Josh!
And, your work is so nice!
rolf

 

[Jamesh Bond]

Sweet. Thx Josh.

 

[dalefuller]

Excellent post, Josh!
And, your work is so nice!
rolf

Damn near magic!

 

[SALTY]

Stunning, absolutely stunning!

 

[Jamesh Bond]

^^ Good post.

________________________

Changing the grind is all about dialing in a knife to the way the knife is used. Imho, production knives are set up (most of the time) for the hardest uses the knife will see because the manufacturer knows that there will be all sorts of people buying their knives and wants to minimize warranty issues.

But the problem with this is that angles are wide (often times 25+ dps, even on many customs I've come across!!), and the grinds are thick - both of which lead to them being poor cutters, which is the point that most of us buy knives in the first place: to cut stuff lol.

To clear up a little confusion... here is a chart (note that the term 'bevel' can also equate to 'grind' so 'primary bevel' also means 'primary grind':

A zero grind simply means that there is no secondary bevel. A true scandi grind has no secondary bevel and is therefore considered a zero grind. Zero grinds can be chisel ground (only on one side) or v ground (on both sides) and can be done in flat, convex, or even hollow I suppose (although the last would be very fragile).

What our goal is, as users, is to dial in our knives to OUR uses... i.e. the heaviest use that our knife will likely see. The goal is to make the knife as thin as possible for our use without compromising strength (the ability to bend back and hold it's original shape under use) or toughness (the ability to dent instead of fracturing). This will yield a knife that cuts WAY better than stock yet is still plenty durable for all of our needs. A side benefit to thinning out the grind is also that it makes touch ups a TON easier =)

Emersons work well with zero grinds because of the stock thickness and relative low grind heights. You wouldn't want to take a ffg spyderco to a zero grind without severe fragility issues. So if it will mainly be a slicer, I would totally zero grind an emerson. If it will be twisting under zip ties and seeing heavier use I would recommend a secondary bevel of .005-.010" thick depending on the heaviest use. All this being said I rarely recommend going over 15 dps, unless and ONLY with a microbevel (for apex stability). But anything more obtuse than 15 for a secondary (for the most part) is not maximizing performance that you COULD have without compromising any blade integrity.

Please take what I say with a grain of salt because I have only ever zero ground emersons, never actually carried and used a zero ground emerson so that's why I err on the side of caution when making recommendations.

Here's a few pics of some zero grinds for thought... The 7's are perfect for a zero due to the super short grind height.

But most of the time I recommend leaving a small secondary bevel like this (it's small but there and adds plenty of stability to the apex) It is also popular to convert to a V edge at the same time =)

Josh I re-read and had a question.

By your 15 dps recommendation, are you referring to a chisel edge or symmetrical edge?

In other words, since you'd get 30 degrees inclusive on a conventional edge, would you shoot for the full 30 degrees if grinding only one side?

Meaning a 30 degree bevel on a chisel edge?

Or are you actually saying to take the single side down to 15 degrees?

I believe the answer is common sense, but I'm an overthinker.

Plus you have some experience that I never will. So. . .

Thx.

 

[REK Knives]

Thanks guys

Josh I re-read and had a question.

By your 15 dps recommendation, are you referring to a chisel edge or symmetrical edge?

In other words, since you'd get 30 degrees inclusive on a conventional edge, would you shoot for the full 30 degrees if grinding only one side?

Meaning a 30 degree bevel on a chisel edge?

Or are you actually saying to take the single side down to 15 degrees?

I believe the answer is common sense, but I'm an overthinker.

Plus you have some experience that I never will. So. . .

Thx.

Well Ideally you would take it down to 30° on the chisel side and nothing on the back... but since I sharpen on a Wicked Edge the back always has a hairline microbevel at about 14-15 dps so I feel comfortable taking the main chisel edge down a little bit more since that micro adds a little stability to the apex. Great question!

 

[Jamesh Bond]

Thx.
My only chisel edge knives are my Emersons.

I find 30 a bit obtuse in this case, so I go to what my eyes guess is about 25 ish.

The smaller angle is easier control when cutting, and with that edge thickness, still decently strong, even with EKI's softer HT.

I wish Emersons were ground on the "correct" side for righties tho. If ya know what I mean.

That one little change would lose nothing and gain everything.

 

[neal70]

Any of my paring chisels( which often don't have a micro-bevel, although I strongly encourage folks to use one) are generally going to be sharpened at 20 degrees for soft woods, and mostly, 25 degrees for hardwood. It really comes down to what your cutting medium is going to be. Plane blade are similar, if I have ones dedicated to type of wood and factoring in knots, keeping in mind that the bed is already angled. Obviously these are just corollaries, but you get the idea. Well martenised steel should be capable of handling a 20 degree(chisel grind) bevel. The entirety of the back of the blade if properly lapped, or flattened is going to support your edge. If all you intend is to cut through paper, or say flesh and cloth, you should be okay. A lot is also dependent on getting the accurate heat treat too, as previously mentioned.
Thanks, Neal
Ps-thanks Josh, some truly beautiful work-and photos!

 

[falar]

I love the cutting performance of zero edges.

I have a Super CQC-8 I've EDC'd for years and despite never wanting to use it as a "utility knife" well, the workday disagreed and I've cut many a copper wire or other hard thing and have chipped the edge in a few spots and it could use a touch up. I wonder if its thick enough to do well with a zero edge? Maybe even hollow instead with a secondary (like hollowground swords) for more scliciness

 

[CPP]

The OP specifically mentioned having a zero-grind done on an A100. The A100 comes with a V primary grind so it seems this process would not be possible.

 

[falar]

I should have my Super CQC-8 back with a near-zero edge from Josh this week. A V primary grind won't prevent you from putting on a zero edge.