This sharpening guide is lifted directly from the pages of Daryl Caswell’s, Reed Knife Sharpening, A Guide for Reed Makers, 2nd Edition. I highly recommend you purchase a copy of this little paperback book. It will provide a great deal more information than I can give you here. It is writtern specifically for sharpening the Landwell double-hollow ground knife as seen in the photo below, but his techniques will sharpen any double-hollow knife well. You cannot go wrong with the Landwell knife. It comes in soft, medium, and hard steel, and you must choose left- or right-handedness, or no-handedness if you are an experienced knife smith. It’s a Cadillac of knives, but it carries a commensurate price tag.
What Knife and Stone Should I Buy?
Look For Quality of the Steel, Steel Hardness, and Shape of the Blade
The three main factors to consider in selecting a knife are the shape of the blade, the quality of the steel, and the hardness of the steel.
Steel quality is directly reflected in the price tag of a knife, but there are overpriced, marginal quality knives too, so go with a familiar brand, like Landwell, Rigotti, Nielsen, or Jende, to name a few. Most “student” knives are just not up to standard as a rule. The ones that are, are always changing, going unavailable, being reinvented by another vendor. What works well one year may not the next. This is not the place to economize. Buy a good knife! And buy a heavier knife blade for debarking. Save your finely chiseled knives for the lighter scraping on the blend and tip.
The double hollow-ground is “hollowed” in a concave fashion on both sides of the blade, yielding an extremely thin edge that sharpens quickly with minimal grinding. Its thin blade and light weight make it extremely versatile.
Check out the little popup window and photo on the Forrests Music website explaining these different blades. Click on their internal link What Kind of Knife Do I Need? The most versatile knife that can do all the steps well, is either a double wedge knife or the double-hollow ground knife. If you can buy only one knife, by a thin wedge knife or a double-hollow ground knife. The double hollow knife is shaped like you see in the photo of my Landwell knife, below. If you can afford a second knife, buy a beveled or wedge knife for the initial scraping off of the bark, as explained in the popup. Buying one of these will make your double-hollow knife last many, many times longer than scraping the bark off without one.
Steel hardness determines what kind of stone will best sharpen the knife, how many strokes it will take, and how long the steel will stay sharp between trips back to the stone. Hard steel requires more work on the stone to make sharp and requires some very fine grit surfaces to finish the edge. The softer the steel, the easier it is to sharpen, but the quicker the blade will wear down to the thick part of the blade and need regrinding to reestablish the hollows in the profile. For now, I suggest the Landwell Medium or any Jende knife in right or left hand as suits your purposes.
A Selection of Stones Is Necessary
Now, remember this concept. We use the coarsest stone to “hone” the edge to a finer, thinner texture or to regrind the entire profile of the knife when it has become too thick to get truly sharp anymore. We use a moderately fine stone to create a burr on the edge, which is the ridge of near-microscopic, “frayed” metal formed by roughening the knife’s edge on the stone. Then, we use a very fine grit to polish or “burnish” that edge, and then an extremely fine grit to give it a mirror polish, which is the purpose of using a steel rod to finish your blade by stropping it along the steel. Understand, we maintain that polished edge with a knife steel, NOT a sharpening stone! You will not go back to the stones until the burr is completely worn away by a lengthy period of scraping, usually days, if not weeks. Only then, will you go back to the stone to reestablish the facing angles and reset the sharpening angles. If you learn how to maintain the burr without returning to honing surfaces, but use burnishing surfaces instead, your one good knife can last you literally for years! The concept is that with each increasingly finer surface, with each reduction of grit, you begin no longer to remove steel, but you begin simply organizing the tiny particles of steel along the edge in ever finer textures, until finally the scraping burr left on the knife’s edge is a well-sorted collection of regularly-shaped micro-particles, and it is this perfectly organized uniformity of very small particles that makes the knife feel sharp. This is the job of the knife steel. Mr. Caswell illustrates this with microscopic views of the steel in his book. Tom Blodgett has marvelous step-by-step illustrations on how to reface your knife and form a new burr and bend it to your best working angle, finishing with a steel to burnish the burr. (See link below) Study these books!
Understand the The Burr Works on a Pendulum Swing or Push of the Blade
It’s the burr that scrapes the cane like much polished steel sandpaper. Now, think about this. In heavy scraping, as in debarking, the knife is pivoted against your off-hand thumb, which is resting on or slightly behind the spine of the blade to steady it, while the burred edge is swinging like a pendulum. Therefore, the angle you create by bending the burr in front of the knife edge determines where in the pendulum swing of the knife that the burr will make contact with the cane and begin to scrape. Every reedmaker develops his own set of sharpening angles to create that sweet spot in the scraping motion that feels most comfortable. We all personalize the angles at which the knife is sharpened by trial and error, but use the same sharpening angles everytime you sharpen the knife. It’s critical that you use the same tilt of the blade every time when sharpening the knife, because each time you want to change your feel, your sweet spot, you must take the knife back to no-handedness and totally reform the edge from scratch. So, pick a way to hold the knife and stick with it until you buy a new knife. Tom Blodgett’s booklet, available through Jende Industries, uses a nickel and a dime as references to set the angles consistently. The Jende Book of Sharpening Double Hollow Ground Reed Knives, is just excellent. Buy it! Or use Mr. Caswell’s great illustrations to start with a universal set of workable angles, and don’t get too creative. You can ruin your knife so that it won’t sharpen at all by inconsistently applying your sharpening angles!
Right-Handed or Left-Handed Knives
When you purchase a double-hollow ground knife, it will be either “blank” (Model D Landwell) or have angles preground that preset the scraping face to a left- or right-hand person. If it is a blank, you will need to start with step 1 in Mr. Caswell’s book to establish the handedness of your knife. VERY IMPORTANT: Keep in mind the instructions below are for the right-handed knife. Imagine the instructions in mirror opposition to sharpen a left-handed knife.
THE SHARPENING STONES
The beveled-style knife (the left of the two knives) seen in the above photo is a heavy knife for scraping bark off, which saves the more delicate edge of your double-hollow ground knife for the finer scraping of the blend and tip. They are lying on my fine grit India stone, which over time has turned from red to dark gray with metal filings. Mr. Caswell recommends never cleaning this off the stone, as it makes the stone work better to burnish the burr to a finer consistency. I agree.
Red Fine Grit India Oilstone, Red Diamond Fine Grit Stone
If all you can afford is the bare minimum investment, then buy a “fine grit” (red) India oil stone to finish the blade and a coarser stone such as a “fine grit” (red) diamond stone (See these in the photo) to re-create the scraping burr. An EZE-Lap 600-grit steel sharpening plate (not shown in photo) is, in my opinion, even better, more versatile choice than a diamond “stone.” The India stone is a natural stone impregnated with oil and the diamond stone is a synthetic stone. Use both with some sprinkles of water for a lubricant. The EZE-Lap steel plate, sprinkled with water as lubricant, with 600 grit diamond surface (not shown in photo) is a workhorse that will serve you for renewing your blades and resetting your scraping angles for literally years to come. Two red India stones, one clean for refining the coarse burr and another black with unwashed steel residue rubbed into its pores for burnishing, will set you up for the finer burnishing on the knife steel. Of note, other brands of these steel plates are less expensive but, in my experience, uncomfortably inferior to EZE-Lap, and tend to make my knives inconsistently coarse along the length of the burr. Buy an EZE-Lap plate. Forrests Music has the EZE-Lap in two grits. Get the finer grit of the two.
Another suggestion, born of long experience…buy longer stones, even though they cost more, in 8-inch lengths and at least 2 inches wide, 3 inches wide if possible; otherwise, you will struggle to keep the entire blade on the stone and end up with knives that are only sharp along the midportion of their lengths. You need the entire blade evenly sharpened along its length, so you can use the full length of the knife for scraping. The narrower and shorter the honing surface, the more passes you will have to make to sharpen the knife. This translates to more time sharpening and less time scraping, a lot more time sharpening! Who has time to waste? Buy the more expensive larger stones wherever available.
References: The heel of the blade is next to the handle. The tip of the blade is the last inch or so of the blade, at its very end. The front of the knife blade is the leading face of the blade. The back of the knife blade faces the thread and your body while scraping. The tilt angle is the degree of tilt created by the lifting and holding of the knife’s spine off the stone during the sharpening stroke.
The following angles are for right-handed knives and are a guide until you develop your own angles according to what feels right for you. Remember, all hollow ground knives are not equal. Some have thicker blades than the Landwell knife, which is a medium thickness knife; some are thinner. When buying, you can ask how the thickness and hardness of the knife you are buying compares to a Landwell “medium” knife (they come in soft, medium, and hard steel), and then adjust the angles to sharpen your knife using this guide’s “middle-of-the-road” angles as a reference. Thicker blade, bigger (taller) angles; thinner blade, smaller (flatter) angles. Also, remember that over time, as the knife wears, the edge naturally climbs upward into the thicker cross sections of the hollow grind, and it takes more lift in the spine to roll the burr harder across the thicker edge. This works for a while, until the rolling becomes severe, and the edge is rounding off. Then you either go back to step 1, lay the blade flat on the stone and regrind the edge to a thinner edge, or take it to a blade smith who can regrind it on a wheel, or maybe, just put your money into a new knife. Finally, remember, whatever angles you start using, be consistent from day to day and only adjust to larger angles as the knife refuses to sharpen nicely when beginning at Step 2 and going forward.
FORMING THE BURR
The burr is formed initially by laying the back of the blade flat and rubbing it on the stone. It is then bent to lie forward of the knife’s front edge and refined and constantly maintained so it does not tear at the cane. These steps are outlined in the Caswell book in great detail, but here is a summary.
This process is not the only way to sharpen a knife well. There are many good methods. This is, however, a very accessible guide, and if you follow the instructions correctly, you will not make a mistake and ruin a perfectly good knife by rolling the edge or grinding the blade unevenly. It will get sharp every time you use this method, and by sharpening the knife correctly, it will prolong the life of your knife. It’s safe and effective, but it is not the fastest way to sharpen the knife. Be patient and do it right every time.
Critical: Always sharpen the entire blade on every stroke. A stroke is one forward and backward coupled motion across the stone with no lift in between. Make sure all the blade is on the stone, pushing and pulling it without changing the pressure within the stroke, and always hold the spine of the knife at the same angle throughout the 2-part stroke. Find a stable surface for your stone and a comfortable body position, and always position the stone and the knife blade so your hands and forearms can maintain the angle throughout the length of the stroke. For most of us, that means placing the stone on a level surface and using both hands on the spine of the knife blade so you can hold the blade perfectly steady throughout the sharpening stroke.
THE CASWELL SHARPENING GUIDE: STEPS 1-9
Sharpening Parameters include 1) which side of the blade is down on the stone, 2) the tilt angle you hold the blade at as you sharpen it, 3) how much pressure is used on the sharpening stroke, 4) quantity of strokes on that side of the blade.
Step 1: This step is not needed if the knife is already right or left-handed. Start here only with a completely dull or “blank” (Model D Landwell) knife.
Stone: Fine (red) Diamond Stone. Blade Position: Back of the knife down on the stone. Angle: Basically, flat with perhaps a thumbnail’s thickness lift of the spine just to protect it from being ground too. Pressure: Heavy on the forward; medium on the backward. Push and pull blade with entire knife blade in constant contact with the stone. (Constitutes one “stroke.”) Quantity of Strokes: 10-40 strokes, until the edge is thin (about 0.002”). [Caswell has a black line of this thickness drawn on page 19 of his book for your comparison.]
Step 2: This step will form the rough burr on the back of the blade. It will be refined in later steps.
Stone: Fine (red) India Oil Stone or a 1000 grit Japanese water stone. Blade Position: Front of the knife facing down on the stone. Angle: About ¼” lift of spine. (See References above for an explanation of how to know if you have the right angle.) Pressure: Heavy on the forward; medium on the backward. Quantity of Strokes: 10-20 strokes, until a burr is visible under bright lighting or can be felt along the back edge of the blade, evenly placed its entire length.
Step 3: If you have a knife with a burr already formed but needing retouching, you can start here to replenish the coarse burr in preparation for the refining steps that follow. If you have proceeded from Step 2, this step will smooth off the grind marks from the coarse stone.
Stone: Fine (red) India oil stone. Blade Position: Front of the knife down on the stone. Angle: About ¼” lift of the spine. Pressure: Medium on the forward; medium on the backward. Quantity of Strokes: 10 strokes, until burr is consistently formed down the length of the blade.
Step 4: If your knife blade is made of hard steel, skip this step as it can make the burr too brittle and prone to breaking off during scraping. If in doubt, try skipping it and see if you get enough scraping capability from Steps 5 through 9. If not, go back to Step 3 and start over, adding in this step.
Stone: Fine India oil stone. Blade Position: Back of the knife down on the stone. Angle: About 1/4” lift of the spine. Pressure: Medium on the forward; light on the backward. Quantity of Strokes: 6 strokes, until you can see the burr displaced off the back of the blade’s edge more toward the front of the edge, or feel it to be so. (Be careful!)
Step 5: Now, you are at the fine honing stage of blade care. This is where you begin to routinely touch up your knife while scraping the fine tips that require so much control.
Stone: Fine India oil stone. Blade Position: Front of the knife down on the stone. Angle: About ¼” lift of the spine. Pressure: Light on the forward; light on the backward. Quantity of Strokes: 7 strokes, until the coarser aspects of the burr peel off, leaving a fine, sharp scraping burr.
Step 6: Here, you further refine the burr and make it stronger and smoother.
Stone: Fine India oil stone. Blade Position: Back of the knife down on the stone. Angle: About ¼” lift of the spine. Pressure: Medium on the forward; light on the backward. Quantity of Strokes: 7 strokes, until the burr feels quite refined.
Step 7: This step will maintain the flat surface of the natural stones and continue to refine and polish the burr in smoothness. Note: The sharpening stroke is modified in this step and the next to set the scraping angle into the blade and ensure that the natural stone surface is kept flat.
Stone: Fine India oil stone. Blade Position: Front of the knife down on the stone. Hold the knife not at a diagonal, but hold it on the end of the stone, parallel with the edge. The knife will be fully perpendicular to the stone and remain that way throughout the stroke. The heel of the knife is on the stone to the handle hilt. Push the blade down the length of the stone for about two-thirds of its length, then begin moving the knife forward and at a diagonal, so that the tip slides onto and finishes on the far end of the surface of the stone. The return is done in mirror like fashion. Angle: About ¼” lift of the spine. Pressure: Light on the forward; light on the backward mirror movement. Quantity of Strokes: 3 strokes.
Step 8: This step is critical. Here, we set the scraping angle into the blade. That is, it bends the burr less or more according to how far you are lifting the spine of the knife. The amount of bend of the burr under the edge of the knife affects where, within the pendulum motion of the scrape, the burr begins to scoop cane.
While scraping the cane, the spine of the knife is anchored against the offside thumb, so only the lower, contact edge of the knife is swinging forward of the thumb, across the surface of the cane. Every reed maker learns the particular angle of sharpening that makes the knife begin to bite at the “right” spot in the scraping motion for optimal control. It’s all about “feel.” This is why your sharpening angle needs to be very consistent from step to step and why I say the ¼” suggestion is just an approximation. Your sharpening angles are unique to you and the thickness of the blade you are using.
Stone: Fine India oil stone, or a hard Arkansas stone can be used. Blade Position: Back of the knife down on the stone. Use a mirror image of the modified sharpening stroke you just used in Step 7 beginning on the opposite end of the stone, as you have flipped the knife over. Position the blade parallel to the end of the stone and maintain this position as you push the blade across the stone for ¾ the length of the stone and then start sliding diagonally to bring the tip onto the surface. Do the mirror movement on the return. Angle: About ¼”. Pressure: Medium on the forward; light on the backward. I want to feel the knife gently biting into the stone on the forward movements. The lighter backward pressure ensures I don’t drag off and tatter the burr I’ve worked so hard to refine and smooth and bend into place. Quantity of Strokes: 3 strokes, until I feel the knife blade evenly biting on the forward and sliding with light friction on the return.
Step 9: This is an optional stroke to “set” the finished edge. I use it, because I can tell it works.
Stone: Fine India oil stone. Blade Position: Front of the blade facing down on stone. Angle: Lying flat on the stone, blade perpendicular to the stone. Pressure: Light. Quantity of Strokes: 1 stroke, while lying flat and pulling the blade straight off the stone to remove most of the remaining loose metal particles that are still clinging to the burr in spite of all the refining strokes you have just worked your way through.
Test the results by lightly scraping at the surface of your thumbnail. A properly sharpened knife will grab and hold the surface of your thumbnail with only the weight of the blade resting across it, and it will get busy scraping with only very light pressure, almost the weight of the blade only to scrape aggressively. How sharp is sharp enough is subjective. When you are learning to adjust reeds, you may not want a knife quite as sharp as I do. You may want to scrape less cane with more scrapes so you can more gradually feel your way through the adjustments. What is not sharp enough is when you cannot get the cane to come off in delicate, tiny, powdery residues while using no more pressure than if you were brushing the reed’s tip with the tip end of a down feather. You can scrape the thicker parts of the reed with a “kind-of” sharp knife, but not the tip. There, it must be strictly sharp enough, or it’s a no-go!
If you’ve gone through all the steps and the knife scrapes pretty well, but you feel like you almost need to push down to get it to really get to work, it’s not sharp enough. Try going back through the steps and get it more exactly right. Your hands will develop dexterity and sensitivity with practice. And, if you’re sharpening a different double-hollow ground knife other than the Landwell, it’s also possible that your angles may not match your knife’s thickness. They may be too severe or too shallow for the thickness of your particular blade. Remember, the Caswell angles are suggested for a medium thick blade. Is your much thinner or thicker? Adjust your angles up or down; spine up for thicker blades; spine lower for thinner blades. If you’re new at this, most likely, your sharpening strokes are not “quiet” and consistent in their angle and pressure throughout. And, just perhaps your type of stone and the hardness of your knife’s steel aren’t the perfect marriage.
As far as angle choice and the feel of the scraping motion in your hands, if you feel the knife starting to pull at the cane too soon in the stroke, then you’re bending the burr a little too aggressively with too much tilt on the spine in step 8; visa versa, if the knife starts scraping too late into the stroke for your comfort. Finally, if the knife is grabbing the surface of your thumbnail and scraping well, but the scrape doesn’t leave a smooth, almost polished surface on the cane, then try using micro-finishing lapping paper, such a 3M makes, in increasingly fine grit to polish the burr to an incredible edge: yellow (12microns) 1200 grit, blue (9microns) 1800 grit, brown (5microns) 4000 grit, and pink (3microns) 7000 grit. It is self-adhering, in 8-1/2 x 11 sheets, and can be cut into strips and stuck to any perfectly flat, nonporous surface that you can scrub clean of the paper when it wears out. This is a very thin but tough polyester-reinforced paper, so use delicate light strokes in the manner outlined in Step 5 and the Step 6, and lift the knife off the end delicately or you will cut the papers. If you have a fine leather strop, use it next, and put some black compound on it, and polish the burr with it using Step 5 and Step 6.
In general, the finer the polishing surface, the less pressure is needed to get the sharpness. If you have done the preliminary Steps 1-9 with the coarser diamond and India stones well, the lapping paper will put a very sharp polish on that burr. Then stand way back from the reed, folks, cause it’ll scrape the hair off a wild hog’s back at a dead run! Woo-hoo! You are done!
HELP FOR KNIFE KLUTZES AND FOLKS WITH REPETITIVE USE LIGAMENT INJURIES
Knife Sharpening Systems
There are jig devices that will do all this holding of perfect angles for you, but before you consider investing in one, ask the manufacturer if they have specifically adapted their product for musicians who scrape reeds. To resurface my older reed knives, I use the Wicked Edge with a Tormek small kitchen knife adapter that grips the handle of the knife. Many of these jig systems will not hold the reed knife by the handle. If the knife blade itself must be clamped in the jig by the spine of the knife, the clamps will get in the way. They are designed for kitchen knives, and most kitchen cutlery has a taller blade than your reed knife. Make sure the jig will hold your reed knife. With all the grits, lapping glass and lapping papers, and the small knife adapter, my Wicked Edge was expensive, and it requires its own work surface. I only use it to reface my reed knives, and when it’s time to sharpen my kitchen knives.
Jigs, like any “system” product, take practice to get good at using them, but they are a miracle product if your hands and wrists are weakened with ligament issues, neuropathy, or arthritis, or if you always feel pretty much like a bear cub wearing boxing gloves. They are superb for creating a perfectly consistent sharp blade from tip to handle and for refacing the reliefs and extending the life of your knife, but they can be very aggressive at removing steel, and you can grind your knife down to a steel sliver in a matter of a weeks if you overuse one. But for periodic knife maintenance, if you can justify the investment, this piece of equipment can be well worth the money, OR you can send your knife back to the manufacturer for regrinding. If you use a lot of knives over a year, this can get expensive. For most reed makers, it’s arguably a good option.
Be patient, take your time, and get the knife right. It will pay for itself in reeds you do not mangle and knives you don’t have to buy over a lifetime. So, there you go!