Sharpening & Honing Professional Knives

Füritechnics is dedicated to developing the world's finest knives and accessories for professional and home cooks. Below is a summary of practical knife sharpening advice, based on the extensive research and development of our engineers and chefs in the areas of knife materials and the technology of cutting edges.

Maintaining very sharp edges on professional knives is a two-part process. The alternatives are:

1. Occasional edge angle restoration with a stone, ‘professional grinding services’, Füri TECH EDGE RestorerTM Diamond FingersTM.

  • Removing excess ‘rounded shoulder’ material from the cutting edge to return to accurate edge angles.
  • Honing on a traditional Steel is the most common cause of ‘rounded’ edges (due to human angle error).
  • A traditional stone requires considerable skill and time, while the TECH EDGE Restorer is much more accurate, and much faster.
  • Diamond Fingers will lightly reshape the cutting edge, maintain accurate 20° flat-sided edge angles, and will not ‘round’ the edge (but does not remove material as fast as the TECH EDGE Restorer).
  • Edge restoration, or sharpening, should be done whenever your honing method ceases to work (due to the edge becoming too ‘rounded’.

2. Regular edge 'honing' with a Steel, Tech HoneTM fingers, or Diamond FingersTM.

  • Simply a process of lightly ‘re-scratching’ the edge to make it sharper (not ‘aligning the edge’ or ‘burr’: that’s a fallacy).
  • A regular Steel won’t maintain the edge shape while honing (human error will destroy the edge bevels by ‘rounding’ them).
  • Diamond Fingers will create a coarse-honed edge and lightly reshape the cutting edge to perfect 20° bevels.
  • Tech Hone (non-diamond) will both hone and maintain perfect 20° bevels, very quickly, and with no skill.
  • Honing should be done regularly (ideally every time you use the knife, or at least whenever the knife feels dull).

Process 1: Restoring cutting edge angles

Professional knives can have their sharp edges maintained by frequent (preferably daily) sharpening/honing on a traditional Steel or Diamond Fingers or Tech Hone.

After several months of manual honing on a Steel, the cutting edges will become rounded, and the sharp flat sides of the cutting edge will need to be restored. This can be achieved by hand on a stone (with a lot of skill), or by a professional knife sharpener (at some expense), or with no skill or expense on the Füri TECH EDGE Restorer (more accurately than any human).

The Füri Diamond Fingers and Tech Hone fingers maintain such an accurate edge that reshaping will rarely be required (only after many months of cutting). However, a knife in bad condition (from lots of Steeling), or with very thick edges, should first be ‘thinned’ to a more accurate edge using the TECH EDGE Restorer (or by a professional knife sharpener who you know is good).

To explain the geometry of the professional cutting edge, and why edge restoration is so important, refer to the cross-section at left:

  • A: The excess rounded material to be removed to return to correct profile – the dashed lines D.
  • B: Centreline of the knife.
  • C: Outer surface of cutting edge, after manual Steeling has rounded the edge.
  • D: Goal of process 1: new straight and accurate cutting edge profile, at 20° each side here, after the rounded material (A) is removed. The angle between D and the centerline (B), is created by the angle between the blade and the stone (though human error rarely creates an accurate angle and flat bevel), or the angle the Edge Restorer automatically creates.
  • E: Steel or stone against the cutting edge (on a broad angle). Note that as wear increases, it becomes more difficult to sharpen the very edge of the knife with a Steel (progressively wider angles are needed, leading to further rounding of the edge).
  • F: Cross-section of knife blade, showing location of cutting edge section in main picture.

1a. Füri TECH EDGE RestorerTM

The Füri TECH EDGE RestorerTM removes unwanted ‘rounded’ shoulder material very quickly and accurately, to quickly shape the edge to the perfect angles. Performs a similar function to the better electric sharpeners on the market, but with much less fuss, more accuracy, less material loss, and less expense. (Electric sharpeners should only be used for regular sharpening if you are prepared to replace knives often: they can remove a lot of material.) Like any edge reshaping method, the TECH EDGE Restorer shouldn’t be used for daily sharpening: it should only be used to ‘fix’ a knife that is badly worn, particularly before honing again on a Steel, Diamond Fingers, and Tech Hone.

If a knife is maintained on Füri Diamond Fingers, and Tech Hone fingers, this coarse reshaping stage may never be required again. Many owners of TECH EDGE only use the Edge restorer once per year or so, because the fingers honing stages are so accurate at maintaining perfect edge bevels.

This is another world-first from Füritechnics: a knife edge reshaper that is adjustable for different cutting edge angles. This was invented so you can easily and accurately put a broad and strong edge on big cook's knives, and a fine and sharp edge on slicing/paring/filleting knives, etc), or create double-bevel edges with fine shoulders at 10° and strong final edge at 20° (technically the ideal edge for cooks).

Whatever angle you set the Tungsten Carbide cutters to, this will be the shape of the cutting edge after several passes through the cutters. The cutters are preset at 20° each side, for an ideal 40° total (same angles as Diamond Fingers and Tech Hone).

1b. Traditional stone.

A lot of skill and time is required to effectively resharpen cutting edges on a stone. There are plenty of other sources of information on this topic, and you should always receive ‘live’ instructions from an expert, so we will confine our advice to restating the most important thing: maintaining the correct angle between the blade and the stone is vital to successful bevel creation. The actual angle will depend on the type of knife being sharpened: a large thick cook’s knife that is intended to be used in tough conditions should have a total edge angle of 40°, so the angle between blade and stone should be half this: 20°. Finer slicing/carving knives can be sharpened to a finer angle: around 20-30 degrees total (halve that for sharpening on each side) on the shoulders. A very steady hand is needed to achieve somewhere near the same angle for every stroke, each side, and no human can really achieve this.

With skill, a stone can be used to ‘thin down’ the shoulders of a knife that has been sharpened for some time and has thick cutting edges (though setting the TECH EDGE Restorer to 10° is faster and more accurate for ‘thinning’ down edges).

The only way to learn stone sharpening technique is ‘hands-on’, with instruction from an expert. Please don’t attempt it without competent instruction.
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1c. Professional knife sharpening service

If you are unskilled with a Stone, and you don’t have a Füri Diamond Fingers or a Füri TECH EDGE Restorer, then you will need a professional knife sharpening service to occasionally restore cutting edge angles. Even if you do own this technology from Füritechnics, thick cook’s knives, in particular, will eventually (5-20 years) wear up the blade and into the thicker section of the knife (making cutting edges very wide and thick), or wear into a ‘reverse arc’ toward the bolster. Good sharpening professionals can thin down the sides of the blade, remove excess shoulder material, and reshape blade profiles, and remove large chips or reshape broken tips. This is all they should be used for (not for regular maintenance), if you want to avoid too much metal removal.  

The real difficulty is in choosing a highly skilled sharpening service. Our recommendation is to only use a sharpening

service that has been recommended by someone who is very knowledgeable. Many sharpening services are general ‘saws, scissors, chainsaws, and knives’ sharpeners, and results can be highly variable, to say the least. However, a highly skilled sharpener of professional knives will be invaluable for the ‘big jobs’: fully restoring old worn or damaged knives.

If you own a complete Füri TECH EDGE Pro Knife Sharpening System, you will very rarely need to seek the services of a professional sharpener.

Real honed edge (side view
of very edge of blade), 40x
magnification. This is good.


Scraped edge from regular
drag-through gadget. 40x. This is bad.

Process 2: Edge Honing

Edge honing is no mystery, for engineers who’ve studied it: honing is simply a matter of 'scratching' the cutting edges of the knife so that new tiny 'saw teeth' are applied to the cutting edge.

The micrograph at left shows a side view of the cutting edge of a knife after honing with the Füri Diamond Fingers sharpener (same edge is created with a diamond steel, if the angle control is perfect). Note the sharp 'gouges' across the cutting edge bevel, produced by the diamond facets. These gouges all meet at the very edge to form a sharp 'micro-serration'. It is the gouges and teeth that provide the 'sharpness' of a cutting edge. Remember this is shown at 200x magnification, so the 'teeth' are very small, and not nearly as aggressive as the supermarket serrated knives!

It is the goal of edge honing, with a Steel or Diamond/Hone Fingers, to produce the sharp 'micro-serration' you see here.

Interesting (for us engineers at least!) common misconceptions include:

Honing only ‘straightens’ or ‘aligns’ the edge. This is only true of edges that ‘burr’, and this only occurs for very fine edge angles: less than 10 degrees each side, so therefore not true for most knives used by chefs, with typically much stronger edges. An edge of 40 degrees total is simply too strong to burr or fold over. For more detail, including microscope evidence, visit the
‘No Bull Zone’!
  • for most knives used by chefs, with typically much stronger edges. An edge of 40 degrees total is simply too strong to burr or fold over. For more detail, including microscope evidence, visit the ‘No Bull Zone’!
  • Honing aligns the molecules of the knife edge. This is funny! Molecules are far too small to be involved in the honing process.
  • Honing should be done with a smooth Steel to make as fine an edge as possible. This is only true for finest slicing knives, and only if the operator is very skilled. For most cook’s knives, a slightly coarser hone is more efficient (lasts longer, and very sharp when the edge is moving).
  • Honing doesn’t ‘sharpen’. High quality diamond Steels and Diamond Fingers can shape the edge, while honing it at the same time (due to the swiping motion being the same; creating the microserration).
  • Butchers, chefs, and knife sharpening services are knife sharpening experts. They know some traditional practical methods, but not always the newer advanced methods, nor the technology behind the process. Results vary widely, because the knowledge is not scientific!

Method 2a. Honing and Sharpening with Diamond FingersTM and Tech HoneTM.

Developed by the chefs and engineers at Füritechnics the patented Füri Diamond Fingers and Tech Hone quickly and easily hones knives of any brand. The specially-curved springs automatically hone the cutting edge to a perfect 20° edge bevel each side, with the ideal edge finish. Note: if salespeople have told you your knife brand has a different angle, ignore them, and convert all your knives to 20° bevels: this is better than 15° or 17° and ‘convex’, and you will be able to maintain this ideal 20° indefinitely, with ease. (Like all the advice here, this does not apply to single-sided, chisel edge, sashimi knives, which are a whole other subject.)  

Our Füri Fingers create the same cutting edge as a Steel (fine micro-serrations) because the swiping motion is the same as swiping on a Steel, but the fingers do it with much more accuracy and speed, and with no special skills. Füri Tech Hone is perfect for finishing edges that have been coarse honed with Diamond Fingers, because the smooth Tech Hone fingers create a smoother and finer slicing edge, while maintaining the same perfect 20° flat-sided bevel shape.

Both Tech Hone and Diamond Fingers will not create an unwanted ‘rounded’ edge (which is inevitable with the human angle error of manual Steeling), because the special curve of the spring fingers are always at 20° wherever they contact the blade, automatically setting the perfect edge angles. Meanwhile, the swiping motion down and back through the fingers creates an accurate professional edge, not the compromise ‘gadget’ edge produced by drag-through devices.


Method 2b. Traditional honing with a Steel

Starting at the heel of the blade (bolster end), the blade travels down the steel in an arc created by pivoting from the wrist (the arm doesn't move much at all). After one side of the blade travels down the steel, the tip of the blade clears the steel and travels back up the other side of the steel, without touching it. At the top of the stroke, the blade is brought back in to contact with the steel to repeat the process on the other side of the cutting edge.

This ‘point-down’ method is more accurate, comfortable and safe than traditional ‘swipe-toward-your-hand’ methods (the worst you can do is hit the cutting board with the knife tip).

The angle between blade and steel is critical, and it can be more easily seen with this ‘point down’ method. Alternate between sides to keep the cutting edge as even as possible. It is not necessary to make a fast swipe, particularly with a diamond Steel: the most important thing is to maintain a consistent cutting edge angle throughout.


The critical issue: maintaining the correct angle between blade and Steel

The most important thing to remember when sharpening/honing a knife on a Steel, is to maintain the correct angle between blade and steel, from top to bottom of the stroke, and the same for every stroke on each side. The angle should be around 20° for most cook’s knives. It is important to not tip the knife over into too broad an angle: this will round off the cutting edges very quickly.

The human error with maintaining this angle is the single biggest contributor to edge damage (more damaging than regular wear)! When the edges become rounded, the blade will slip off onions and squash tomatoes, etc, even though the edge is ‘honed’. At this point, the rounded shoulder material needs to be removed from the edge, to return it to an accurate flat-sided cutting edge, for sharper and safer cutting: back to process 1.



















Process 1a & 2a combined (re-sharpening and honing):

Füri OZITECH Diamond Fingers



Patented by Füritechnics (Australia), OZITECH has 8 diamond-coated spring fingers that act just like small diamond-coated Steels, but with perfect 20 degree angle control. The diamond coating will remove some metal, so this will regrind and sharpen most blades that have been ‘rounded’ from wear and/or honing on a Steel. OZITECH Diamond Fingers also hones the edge at the same time, because the swiping motion is down and across the fingers, similar to the swiping motion across a traditional Steel.

Restaurant chefs and culinary institutions all around the world are using Füri OZITECH to sharpen and hone their knives to a better edge than ever before, more quickly, more consistently, with less down time.

Click here to see more detail on the Ozitech packaging.

FOR THE EXPERTS! The ultimate combination of Edge Restorer, Diamond Fingers and Tech Hone Fingers

The Füri TECH EDGE Pro Knife Sharpening System (patents pending) is the culmination of years of research into cutting edges by Füritechnics’ engineers and chefs. TECH EDGE incorporates all the important sharpening and honing stages into one simple interchangeable handle slot system. TECH EDGE is being rapidly adopted by chefs because it is faster and more accurate than any other method, and it is also simple enough for home cooks to maintain all their knives to professional sharpness.

With this 3 stage combined sharpening unit, the first stage TECH EDGE Restorer would be used to quickly restore old and worn edges, the second stage Diamond Fingers used to coarse hone the restored edge, then final stage Tech Hone to finish the edge to a very sharp final hone. At every stage a perfect 40° total edge angle (20° bevel each side) is maintained. The innovative ‘fast-fold’ handle packs down small for easy storage, and each of the three TECH EDGE stages is interchangeable in the handle slot. A bench mounting bracket option is ideal for commercial kitchens, because it allows the sharpeners to be slotted on the side of benches.

Most days, only a few quick swipes through the Tech Hone fingers is all that is required to maintain perfectly sharp edges.

Compared with OZITECH, TECH EDGE has the added functionality of a much faster and coarser first stage for rapidly ‘regrinding’ edges to the correct bevels, and a finger final honing stage. Only the experts will really feel the difference in the final edge between OZITECH and TECH EDGE. OZITECH is good enough for most chefs too, however, many chefs, home gourmet cooks and sporting knife users are using TECH EDGE to ensure they always have the ultimate edge on all their knives.

TECH EDGE, incorporating the Füri TECH EDGE Restorer, Diamond Fingers, and Tech Hone, makes the ultimate professional knife sharpening solution!

Click here to read more detail in the instructions packaged with Tech Edge.