Simple Straight Razor Honing

When I first became seriously interested in this topic about four years ago, consistently honing a straight razor to the level of keenness required for a close, comfortable shave challenged me. Having earned my living for the past 25 years solving problems like these, I began by searching for relevant scientific literature as well as reading the opinion-based resources of internet forums. I was surprised to find almost no published scientific work, although likely there is a wealth of information in unpublished reports in the research libraries at the Gillette and Schick corporations. The internet forums proved to be a dead-end, although for different reasons. Over the past 4 years, I have learned a great deal about sharpening, honing and stropping and have shared some of that knowledge here.

When I started this blog, just over two years ago, I chose to concentrate on demonstrating what happens at the apex of a blade, particularly since the relevant length scales are much smaller most people can comprehend (or see with even the best optical microscope). When writing these articles, I have made a concerted effort to avoid drawing conclusions, instead just showing what actually happens at the sub-micron scale during the various sharpening processes.  I have chosen not to use this a forum to explain how to sharpen, but rather to provide a resource for people with sufficient interest and comprehension to improve their own understanding.  In this article, I will break with the trend and share a simple and reliable technique for honing a straight razor.

It is usually claimed that honing a straight razor is more difficult than sharpening a knife or other bladed tool. While it is certainly true that some people make it more complicated, it is not necessary to do so. It is also commonly asserted that honing a straight razor requires a set of fine and expensive hones – this is also not true. I demonstrate here that only two hones are required, one coarse hone for expeditiously setting the bevel and one fine hone for polishing away the apex damage created by the coarse hone. The second hone does not need to be any finer than 4k grit. It is also important to understand that scratches in the bevel are of no consequence when the bevel is micro-convex as the scratches do not reach the apex.

I have personally used the approach described below for approximately two years, and have shave-tested well over 100 razors prepared by this approach. I have recommended this technique to people having difficulty honing their own straight razor and have not yet had anyone tell me they were unsuccessful.  To be clear, there are many other ways to accomplish this result; however, this is the simplest and most consistent approach that I have found.

This approach is quick and easy if you are honing a straight razor that has been shave-ready (not a restoration or a factory edge, for example) and not been damaged (no chips that you can feel with your thumbnail) and is not warped. A smiling blade is not a problem, provided you use a rolling stroke to shift pressure along the length of the blade.

If you are unsure of the condition of the blade, raising a burr that you can feel using a 1k stone, as you would when sharpening a knife, is a helpful diagnostic. However, I would only do this once, as it is a waste of steel.  It is important to remove this large burr with edge-leading strokes as the steel near the base off the burr will be damaged from the burr flipping side to side.

The goal of the first step is to remove enough steel from the bevel faces to ensure that they meet and form an apex (usually called “setting the bevel”). Up to this point, the approach for sharpening a knife and a straight razor is essentially the same. Although with a straight razor we want to avoid introducing chips in the edge, something we are less concerned about when sharpening a knife. A straight razor has a narrow bevel angle (commonly 16-17 degrees, inclusive) and is more susceptible to micro-chipping than blades with included angles of 25 degrees or more.

My preference is to set the bevel with high quality 1k stone such as a Naniwa or Shapton to achieve a good trade-off between abrasion rate and the size of the micro-chips in the apex.  Lower quality stones will also work if edge-leading strokes are avoided. As a rule of thumb, using the 1k stone long enough to make black swarf, then ending with about 20 edge trailing strokes is sufficient. The reason for the edge trailing strokes is explained in the series of images that follow.

To show how robust this technique is, for this demonstration I use two of the worst choices for hones that I own, the DMT extra fine (1200) and the 6k side of a King 1k/6k combination stone. The DMT is problematic because it produces micro-convexity and substantial damage and distortion to the apex. The King 6k, although a good polisher, causes significant micro-chipping to the apex when used edge leading.

The first step, here shown with the DMT extra fine (1200) diamond plate, produces a near-triangular bevel but with damaged and distorted steel at the apex. This is all that is required at this step – it is of no consequence whether the blade can “shave” at this point.

GEN_DMTF_20ET_01

Edge-on view of a straight razor honed on a DMT EF (1200) ending with 20 edge-trailing laps.

 

GEN_DMTF_20ET_03

Cross-section view of a straight razor honed on a DMT EF (1200) ending with 20 edge-trailing laps.

 

The second step is to polish the bevel and remove the damaged steel near the apex with a 4k to 8k level hone with about 20 edge-trailing strokes. There is no need for a feather light touch, but the edge trailing strokes should not flex the blade either. The goal is to produce a foil edge – more steel than we want at the apex.  After this step, the blade is in similar condition as it would be when using the Murray Carter 1k/6k method prior to folding the burr by cutting into a piece of wood. In the example here, the blade received 20 edge-trailing laps on the King 6k to produce a micron-sized foil burr.

 

GEN_DMTEF_6k20ET_05

Edge-view of a straight razor after 20 edge-trailing laps on the King 6k stone. The small foil-burr is clearly visible

 

GEN_DMTEF_6k20ET_01

Cross-section view of a straight razor after 20 edge-trailing laps on the King 6k stone. The bevel angle near the apex is less than the innate bevel angle, typical of a foil-burr.

In the low magnification cross-section view (below) a micron-sized foil-burr is observed at the apex beyond an otherwise triangular bevel. The goal of this step is to have the apex “longer” than we require so that there will be no damaged or chipped regions remaining after the strop-based burr-removal step. Again, it is of no consequence whether the blade can “shave” at this point.

GEN_DMTEF_6k20ET_03

Cross-section view of a straight razor after 20 edge-trailing laps on the King 6k stone. The white triangle shows the innate geometry of the blade, and small (1 micron) foil burr is visible beyond that triangle.

 

The third step is to remove the burr using the hanging denim strop with metal polish. This burr-removal technique was detailed in Burr Removal – part 1. I normally use a strip about 4cm wide and 25cm long, but you can make it larger if you prefer. As a rule, I do 30 laps. Again, there is no need for feather light strokes – on a weigh scale I would expect to see between 100g and 150g. I tape the denim strip to the edge of the bench with duct tape, and do not pull nearly hard enough to pull it loose. This will micro-convex the blade, removing all traces of the foil-burr. I replace the denim strop when it becomes dark and glazed, after ten to twenty uses.  I have analyzed and tested a variety of metal polishes and all performed similarly.

The purpose of this third step is to micro-convex the apex and remove the foil-burr in preparation for the diamond on leather strop which will then shape the apex for shaving level keenness. As I have shown previously, diamond on leather will convex the apex but not remove the burr which forms as a consequence. A typical example of a foil burr that results when transitioning directly from a hone to a diamond on leather strop is shown in the two images below.

 

GEN16k_p25PD_roo_01

Edge view of a straight razor honed with a Shapton 16k to produce a triangular bevel and then stropped on a 0.25 micron poly-diamond loaded hanging kangaroo leather strop. The approximately 3 micron long foil-burr is clearly visible.

 

GEN16k_p25PD_roo_04

Cross-section view of a straight razor honed with a Shapton 16k to produce a triangular bevel and then stropped on a 0.25 micron poly-diamond loaded hanging kangaroo leather strop. The approximately 3 micron long foil-burr is clearly visible.

 

The denim stropping step not only removes the burr formed by edge-trailing strokes on the hones, but the “pre-existing” micro-convexity that it imparts will prevent the formation of the foil-burr that typically forms when stropping on diamond-loaded leather (shown above). The foil-burr (above) results from incomplete (micro) convexing of the apex.  The result of the loaded denim stropping step is shown below.

 

GEN_6kET_FlitzDen_01

Edge-view of straight razor honed with the DMT EF and King 6k following 30 laps on the (Flitz) metal polish loaded denim strop.

 

GEN_6kET_FlitzDen_03

Cross-section view of straight razor honed with the DMT EF and King 6k following 30 laps on the metal polish loaded denim strop. The apex is keen and well formed.

 

GEN_6kET_FlitzDen_05

Cross-section view of straight razor honed with the DMT EF and King 6k following 30 laps on the metal polish loaded denim strop.

With the denim strop, there is some care required to ensure that suitable downward pressure is used. With too little force, the apex will not be sufficiently convex to avoid the formation of a foil-burr with the diamond on leather strop. I typically use the same force on all strops, both loaded and clean.

GEN_16k_Flitz_light_03

Cross-section view of the straight razor stropped on the Flitz polish loaded denim strop with relatively light force (less than 50 grams equivalent). The near apex bevel angle has only increased by 3 or 4 degrees and the apex is not sufficiently keen for shaving.

With too much force, the apex will convex too much and not contact the surface of the diamond on leather strop.  Too much pressure will also turn the strop black more quickly as the entire bevel is convexed (and more metal is removed).

GEN_flitz_heavy_03

Cross-section view of the straight razor stropped on the Flitz polish loaded denim strop with relatively heavy force (estimated to be 300-400 grams equivalent). The near apex bevel angle has increased by 10 degrees. The apex is relatively keen and well formed, although not quite sufficient for shaving.

 

Typically, the blade will shave reasonably at this point in the procedure, although it is not likely to tree-top fine arm hair or pass the hanging hair test with any great success without additional stropping on clean or loaded leather.

The fourth step is to clean up the apex and maximize keenness after the denim. This is easily accomplished by stropping on smooth leather loaded with diamond spray . Again, as a rule, I do 30 laps. In this example, a hanging kangaroo leather strop loaded with 0.25 micron poly-diamond spray was used. I typically use a latigo leather strop for this step – there is no need for exotic leathers.

GEN_EF_6k_p25roo_03

Cross-section view following 30 laps on the 0.25 micron poly-diamond loaded kangaroo leather strop.

 

GEN_EF_6k_p25roo_07

Cross-section view of the blade after the diamond sprayed kangaroo leather strop.  The white triangle shows the innate bevel angle and amount of steel removed by micro-convexing the blade.

 

Depending on the pressure applied during the stropping steps, a very small (but inconsequential) burr may remain on some parts of the blade.  The foil-burr shown below is not typical, but even in the event one of this magnitude is formed it is not a problem.

GEN_EF_6k_p25roo_02

Edge view of the blade after the diamond sprayed kangaroo leather strop.

This inconsequential burr can easily be removed by stropping on clean denim. Any clean linen strop component will suffice.

GEN_clean_den_01

Edge view of the blade after the clean denim strop.

 

Finally, prior to shaving, I strop on clean leather, 30-50 laps. This will deposit a thin layer of organic “lubricant” on the surface of the blade, as well as ensure that the apex is aligned.  At this point, the blade should easily “tree-top” the finest arm hair and score HHT-5 on the hanging hair test.

 

  137 comments for “Simple Straight Razor Honing

  1. Zen
    May 31, 2021 at 6:52 pm

    I have a big question for you!
    I purchased a Thiers Issard just honed from the factory! I asked to verify if it will have come honed properly!
    But it has verified what I feared!
    The razor is honed and pass the test of cutting beard on arm or single beard hanging but can’t shave properly neither I have done 200 passes on the short paddle strop I have!

    So the big question what king of sharpeness has this razor?

    What work of honing have I to do???

    To me this razor going by intuition it seems like if has stopped to a 5000 K stone!
    But there is the risk I would go back if is not this!
    So I should probably starting from the 12 k superstone Naniwa but I’m not sure about that!
    Because I don’t know what have done in the factory for honing!!! I will contact the factory but for the moment the razor is completely out of order for not being sharp for a normal shaving! without pulling skin and beard!!! Please tell what you think I should do! Obviousily I will contact the reseller but I think he will not help me to solve the problem! because I had the same problem with other razor I had to throw in the garbage! Thanks very much for your help

    Like

    • June 1, 2021 at 4:03 pm

      I have a few Thiers Issard razors, but I haven’t bought one for about 5 years. That last one was severely warped and I returned it. I don’t have any experience with their current honing quality, but I did find all of them required a fair amount of work to get them to a geometry where the could be honed on a flat stone.
      If your razor can nearly pass the HHT then it is definitely within stropping range of shaving. A pasted strop followed by a good clean strop should get you there. If you want to shave with a straight razor, you really need to invest in a good hanging strop, a paddle strop is ok for maintenance, but it’s no substitute for a proper strop.

      Like

  2. Tommy Atwell
    June 16, 2021 at 12:46 am

    Hi! First, I’d like to say that your work is very informative and I appreciate it very much!

    Second, in your article on “The diamond plate progression” you showed that a 325 grit DMT plate was able to make a blade quite sharp. Would you recommend using that technique for a kamisori razor short term until I can afford the higher grit whetstone as well as the straps and compounds?

    Like

  3. Derek Louey
    July 8, 2021 at 7:01 am

    With regular daily shaving and assuming no misuse of the blade, how often do you have to go back and reshape the edge with your sharpening stone. How far back in the progression do you have to go? Do you have a daily maintenance stropping routine? Do you ever steel a shaving blade and when?

    Like

    • July 8, 2021 at 7:37 am

      Personally, I usually get 5-7 good shaves before I do maintenance on a the hone – about the same as I get from a Feather Artist Club blade. Someone with softer whiskers than me could potentially go for months with only linen/leather. I have used the method described here with only a Shapton 4k GS for almost 7 years and not once gone to a coarser stone with one of the razors in my standard rotation.

      I typically use the linen sparingly, always after shaving to clean the blade but rarely before – usually just 60-ish laps on the leather before shaving.

      Steeling IS micro-beveling and you cannot micro-bevel a straight razor or even a knife with similar geometry without applying catastrophic lateral force to the blade, resulting in chipping. Instead, we use a strop to gently micro-convex the apex.

      Like

  4. Finn Eh
    August 17, 2021 at 4:19 am

    Todd, thank you for all the work you have done.
    This past week, I have been devouring your blog, article after article. Your writing style is very clear and understandable, yet you explain topics in depth, providing evidence instead of relying on opinions. Great work 🙂

    I have a few questions regarding stropping. I already own a tensionable paddle strop by böker (“Schraubspannriemen”).
    1. Do you think this will work similar enough to a hanging strop, provided I keep the tension rather low?
    2. The backside is leather loaded with green compound. Do you think this has any use in SR stropping, or is the open fabric (Linen/denim etc.) needed with coarse compounds like this?

    I plan on making a denim strop. Do you think just using a clean denim strop and a clean leather strop could work in a honing progression coming off a shapton 8k/12K or a coticule? If I understand correctly, the compound mainly speeds up the micro-convexing, so with enough laps, using clean strops could still work?

    Like

    • August 18, 2021 at 9:28 am

      Based on my testing, this approach is not very sensitive to the (diamond loaded) leather strop. So I would expect that a paddle strop would work just fine.

      I don’t see any value to using pure chromium oxide as a stropping compound; however, “green compound” is often a mixture of aluminum oxide and chromium oxide, where the aluminum oxide dominates the performance – these type of compounds would work just fine on denim. I would not expect anything positive coming from coarse compound on smooth leather at straight-razor geometry.

      It is true that the compound mainly just speeds up what the bare substrate would accomplish, but it can be a thousand-fold increase.

      Bare linen and leather do work for many people, it just requires greater skill with the stones. The technique I describe here is meant to remove the need for that effort/skill on the stones.

      Like

  5. September 7, 2021 at 8:29 pm

    Thank you for all of the time and effort you put into this website—it’s a tremendous wealth of information.

    I’m wondering whether you might have any suggestions for a next-best alternative to a leather strop, as I don’t use animal products.

    Any help would be greatly appreciated!

    Like

    • September 7, 2021 at 8:49 pm

      I know Tony Miller makes a vegan razor strop, but I have no experience with it.

      Leather is particularly effective because of the nano-scale fibrous nature of the surface – I don’t think this is something that can be duplicated with a synthetic material – the palm of your hand is likely the best non-animal strop you will find.

      Like

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