A simple honing method with DMT-E, Belgian Blue Whetstone and Coticule
From the dawn of mankind, sharp utensils have always been important to humans. The art of sharpening must have been one of the first activities of man where a scientific attitude was apt: experiment - observe -repeat. In the stoneage sharpening was as straightforward as knocking flints of a suitable stone. Which stones were most suitable? How was a stone to be hit, to end up with the sharpest flints? Man learned trough trial and error, which is the basis of all empirical science, and shared his knowledge with others, generation after generation. Since then, brass, iron and steel have each on its own revolutionized the craft of tool-making, but the didactic principles of how knowledge is passed on, have not. Men have at least been shaving facial hair since Roman times, and ever since, boys and men have been wondering, learning and teaching. I cannot write anything about honing today without paying tribute to the countless anonymous men who walked my path before me. Two of them I can call by name: Josh Earl and David Polan, who are both very respected members of "StraightRazorPlace", an online community, founded by Lynn Abrams, for those who indulge themselves in the nearly lost art of shaving with a straight razor. Without those men, I would lack the knowledge and confidence to write anything about sharpening razors today. Nothing of what I'm about to write down is carved in stone, but the paradigm I'm about to propose for properly honing a razor is one that stays close to the bare physics of sharpness, and approaches its goals one step at the time. It's easy to grasp what is happening during each step and if the results are off it's fairly possible to pin down the problem to a particular stage in the honing sequence. My paradigm uses a DMT-E diamond hone for perfecting the bevel of a razor and Belgian natural whetstones for further refining and polishing that bevel to a comfortable “shave-ready” edge. The Belgian natural hones come in two varieties: the BBW (Belgian Blue Whetstone) and the infamous Coticule (a pale yellow stone). This does by no means imply that I consider other hones or methods inferior.
I like Coticules for being traditional and natural, for their ease of use and the outstanding quality of the resulting edge. The DMT is versatile and fast, does not require periodical flattening. Both the Belgians and the DMT are not porous, they do not glaze and they are always ready to go. Both the DMT and the coticule are used with water, without the need for pre-soaking. If you stick with the 6”X2” DMT-E and a similar size BBW and Coticule, you have a very cost-effective solution that provides a life-time of smooth shaving edges.
Warning! DMT's cut deeply & may not be suitable for use on some older razors e.g. old Sheffileds.
There's nothing enigmatic to honing a straight razor, as long as one realizes how easy it is to throw a monkey wrench in the whole process, and instantly kill all chances for success. For those who share my experimental nature, I must emphasize to suspend any variation till you are sure you can get results with the paradigm as it is described.
- 1 Meet the hones
- 2 Step 1. Perfecting the bevel on the DMT-E
- 3 How to probe the edge
- 4 Step 2. Refining the edge on the BBW
- 5 Step 3. Polishing the edge on the coticule
- 6 Aftercare
- 7 Final notes
Meet the hones[edit | edit source]
This basic honing Paradigm uses the following hones:
- DMT-E (continuous surface from diamond monocristals, grit 1200)
- Belgian Blue Whetstone
- Coticule Whetstone
All hones must be completely flat. The BBW and Coticule need to have chamfered sides. On a hone with a sharp 90° side, there's a high risk that the edge might catch during the slightest tilt in the honing stroke. Needless to say the result could be a disaster if that happens.
The honing stroke has to be performed in the same fashion on both hones: (see figure 1)
The razor lies flat on the hone (1) and is pushed over the hone with a diagonal movement, the edge leading. A short duration on the heel provides even sharpening giving a slight radius to the stroke. (2) Pressure is as minimal as possible, but enough to assure a nice even stroke, without tilting the blade as it protrudes over the side of the stone. The razor is turned over its spine and moved laterally till the heel lies back on the hone again (3) Then it is pulled back, again with the edge leading (4). Such a complete back and forth movement is counted 1 complete stroke. This is the standard X-stroke. Variations do exist, but they fall beyond the purpose of this text. The reason for the diagonal movement is to maximize the contact of the blade with the hone. Some razors have a tiny bit of warp in the blade, which prevents the edge from touching the blade along the entire length. Due to the continuous variation of the points of contact, the X-stroke rules out the possibility that some parts of the edge are poorly honed.
Keep the water (or slurry) eyeballed while honing. How the wave behaves in front of the blade and in particular, how it runs up the edge, offers a good insight in how the edge is contacting the hone and how the edge is developing.
Important notice: during honing it is important to rinse the blade well (preferably under a running tap) before wiping it with a cloth or tissue. Otherwise residual honing particles might leave stray scratches on the edge and blade. It is of equal importance to prevent low grit residue to contaminate higher grit hones. Honing a razor is a meticulous job.
Step 1. Perfecting the bevel on the DMT-E[edit | edit source]
The goal of this first stage is dual:
- to make both sides of the bevel completely flat and even, free from micro-chips and damage, free from any trace of corrosion.
- to make both sides of the bevel meet each other in the smallest possible line. This defines the sharpness of the edge.
Subsequent steps are completely futile when these two goals are not first successfully achieved on the DMT.
METHOD: moisten the hone with some clean water and perform X-strokes. If the stone is rejecting the water, a drop of basic dish-washing detergent will solve this. Pressure must be kept low. Diamonds cut steel easily. Concentration is key: the razor must remain flat on the hone at all times. Lifting the spine, however briefly, might set you back a considerable amount of strokes. The razor must not be tilted as it protrudes beyond the edge of the hone. It may take a considerate amount of work to achieve a perfect bevel. It doesn't matter for the final results if one does too much work here. From a certain point on, the edge won't ameliorate any longer, but it won't deteriorate from doing too much. The only downside is a waste of precious steel. The shape of the bevel is of utmost importance for the final honing result. Work that is neglected here cannot be compensated during the next steps in the process.
The above image clearly shows that the amount of steel, that needs to be removed from the "cheeks" of a rounded or convex-shaped bevel, can be quite significant.
How to probe the edge[edit | edit source]
- Main article: Sharpness tests explained
A number of tests are available for evaluating the progress of the honing sequence:
The edge can be closely inspected under a good light source. Closely observe how the light reflects from the bevel. A good bevel will only reflect light in one direction. Light shining in odd directions reveals parts of the bevel that are not yet in one plane. Spot for such occurrences coming from the very edge of the bevel, as they are a clear marker for residual roundness. Cover the bevel of the razor with a waterproof felt tip marker (degrease with some alcohol first if the blade was oiled for rust protection) 2 or 3 X's over the hone should completely remove the ink from the bevel. Ink remaining at parts of the very edge of the bevel reveal residual roundness. Ink remaining on complete parts of the bevel reveal spots where the bevel is not making contact with the hone, possibly due to some form of slant in the blade and/or spine.
(Fumbling just a little bit by dropping the angle a fraction of a degree at those spots, as you push the blade over the edge of the hone during the X-stroke, should clear out minor issues in the straightness of the blade. More severe cases ask for different measures, that fall beyond the scope of this text).
It is possible to inspect the edge under a stereo microscope, or some other magnification device. Damage and corrosion can be clearly seen that way. Visual inspection tells little to nothing about the keenness of the bevel, as it is not possible to see the width of the line where both bevel panes meet.
The Thumb Nail Test (TNT)[edit | edit source]
Put the cutting edge of the razor on your moistened thumbnail and drag the entire edge slowly over the nail, as if you were trying to slice through it. Don't apply any more pressure than what the blade offers by its own weight. It is advisable to perform this test only during step 1 on the DMT. The fine result from a finishing hone such as the coticule might suffer from performing a TNT. It is best to do another 20 ultra light laps on the DMT after your last TNT checks out fine.
There are 3 possible sensations:
- The blade sinks a bit in the thumbnail (leaving a scratch) and one can sense a small but clear drag while drawing the edge along the nail. This is a sign of sharpness and marks that the work on the DMT is coming to an end, at least, when the same result is present on the entire edge of the razor.
- The razor skates over the nail without any resistance and without leaving a scratch. The edge is still dull. More work on the DMT is needed.
- The razor abrades the nail and feels more like a file than a knife. There is damage present on the edge. A lot of work will still be required on the DMT.
The Thumb Pad Test (TPT)[edit | edit source]
Hold the opened razor upright in one hand, the cutting edge facing towards you. Place the fingers of the other hand behind the blade and place the tip of your thumb on the cutting edge, as if you were aiming to slice the tip off your thumb. Don't use any pressure, or you will cut into your thumb. Now, make a short, gentle motion across,not down the blade, with your thumb. A sharp edge will reveal itself as it tries to adhere to the thumb, sticking to the skin, as if it was covered with caramel. This quality should be probed along the entire length of the edge. With some experience one can learn to differentiate between various degrees of sharpness by simply performing a quick TPT. During the formation of a good bevel, it is quite normal for the edge to show parts where it is very keen already while other parts may still need a few additional strokes. The TPT is not an easy test to learn, but it is one of the most reliable test to probe for the sharpness of a cutting bevel.
The Arm Hair Test (AHT)[edit | edit source]
After the DMT, a razor should shave arm hair without much effort, certainly when the arm is wetted with some water. A superb bevel will pop some arm hairs even if it floats a few mm above the surface of the skin. Hair types vary & this test is not definitive. Failure does not absolutely indicate an incomplete bevel.
The Hanging Hair Test (HHT)[edit | edit source]
Take a clean, preferably thick head hair between thumb and index finger. Press the edge of the razor against it at about half an inch from where it is held. Don't use a slicing motion. A razor with a perfect bevel coming off the DMT should catch at the hair and sever it. It is acceptable at this point if you need to drag the hair a bit across the edge. Finalizing your efforts on the DMT with ultra light laps can make all the difference in this regard. Hair types vary & this test is not definitive. Failure does not absolutely indicate an incomplete bevel.
Step 2. Refining the edge on the BBW[edit | edit source]
It is imperative to use this hone with a light slurry, because otherwise it cuts too slow to gain reasonable results. The slurry is produced by moistening the stone with clean water and rubbing the surface with another piece of BBW, or with the DMT (if you’re without a rubbing stone). This slurry is not to be made too dense. A watery, milky consistency is sufficient. A creamy consistency is too thick, and while it may cut faster, it does not leave the keenest possible edge, due to the abrading effect on the very tip of the bevel as it is pushed trough a dense slurry. When such a slip-up happens, the results on the TPT will reveal it. In such case, it is best to revert back to the DMT-E for a few light strokes, and start over with a lighter slurry on the BBW.
It should take about 50 to 100 laps to replace the scratch pattern from the DMT with the one from the BBW. Shortly after that goal is achieved the edge keenness will level off a the maximum that can be reached with the BBW. At this point, The slurry must be thinned with a few drops of water every 10 strokes. Continue honing till the slurry is completely washed down. Assessing the edge for sharpness should be done by means of the TPT. If everything checks out fine, the blade should be rinsed under a running tap and wiped clean.
Step 3. Polishing the edge on the coticule[edit | edit source]
During this step the edge is polished and smoothened. For this kind of use, a slurry is NOT to be raised on the Coticule. This achieves the keenest possible edge. Approximately 100 very light laps should suffice. The TPT should give a clear distinctive feedback of ultimate sharpness. Rinse and wipe clean. The razor can now be stropped.
Aftercare[edit | edit source]
Stropping 20 laps on canvas and 60 laps on clean leather before each shave should keep the razor in optimum performance for a few weeks to months depending on various factors, such as: steel alloy and hardening, beard coarseness, before-shave-preparation, shaving technique, proper care and storage of the razor, stropping technique.
Final notes[edit | edit source]
Some Coticules are fast cutters when a slurry is raised. Those specimen are quite capable of doing the work of the DMT-E in the above honing paradigm. Use a milk-like consistency for the slurry and gradually wash it down to plain water during your last 40 strokes. Then proceed to the BBW for step 2.
When normal stropping no longer brings the blade in superior shaving condition, the edge can be touched up by repeating steps 2 and 3.
--Bart 22:15, 30 November 2008 (UTC)