Tutorial Razor Stones Part 1

Discussion in 'Tutorials' started by Steve56, Jul 19, 2018.

  1. Steve56

    Steve56 Well-Known Member

    OK, let's get started! Installment 1 on hones (please forgive formatting...)

    1 Choosing Hones for Razors

    Properties of a razor hone

    A razor finishing hone has to be:

    a) fine. If it isn’t fine enough, nothing else matters. How fine is fine enough? 8k is usually considered the lower threshold for razor finishers, using anything finer likely will depend on your taste in edges, beard, skin, etc. A Naniwa 12k Superstone is an excellent finisher.

    b) Have a narrow grit distribution. Stones, even synthetics, are not a single grit. If your 12k has a lot of 3k grit in it, that’s a problem for a razor, less so than a knife. It also needs to be harder than knife hones. Soft stones tend to auto slurry more and convex the bevels more, again not that much of a problem with most knives.

    c) Not have large clumps of grit or grit/binder that can turn loose and damage an edge that’s only 0.5 microns wide at the apex of the bevel. It needs to uniform and consistent.

    d) The shape of the grit, or as Takeshi Aoki put it, ‘how the grit lays on the hone’ is worth considering. An example is a coticle. Coticules struggle to reach 8k, yet they are known for their smooth shaving edges. A Shapton Glass makes sharp edged scratches, the coticule wider shallower scratches because the garnets are round rather than angular. Barber hones are also coarse but the grit becomes flattened or burnished at
    the surface and effectively produces finer striae than the grit would suggest.

    It’s tempting to try and save money by buying a cheap hone for razors, but although hones look very much the same, cheap ones will likely not meet criteria b and c above. That may be OK for a knife hone (a pot roast never complains) or garage tools, but a straight razor is a different thing.

    Sizes

    Most synthetics are designed for tools and knives and are roughly 8-1/4” (205mm) x 3” (75mm) and the thickness varies. Smaller ones can be found in many sizes, but you’ll have the best selection in this size, also called a bench stone.

    Many natural hones have different sizes, Japanese naturals in particular have a range of defined sizes that were named for the most part by the number of them a woman or young person could carry down the mountain.

    Most European hones are narrow, 2” wide is fairly common but narrower ones are common too, especially in the shorter sizes. I really don’t know the reason for this especially with slates, the material was common and cheap enough to cut any size, yet almost every one was narrower than a straight razor blade.

    The Japanese and the coticule producers also sold bouts or koppas, small irregularly shaped pieces, and I’ve seen similarly shaped Thuringians.

    Hardness

    Most razor hones, especially finishers are harder. Hardness and fineness go
    hand-in-hand especially with Japanese naturals and Arkansas, though the density is
    usually what’s measured with Arkansas stones. If a stone generates much slurry of its
    own, it is usually not a top tier razor hone, at least not a top tier finisher. Note that
    almost all synthetics will slurry a little by design, that’s how fresh grit is brought up to
    keep the stone cutting as designed. A softer stone will also need to be lapped more
    often - more on that in the section on flattening and maintaining hones.

    Here’s a simple ranking of synthetic stone hardness, soft to hard: King -> Naniwa Super Stone -> Shapton Glass HR -> Shapton Glass HC and Pro/Ho-Na-Kuromaku -> Naniwa Chosera/Snow White -> Suehiro Gokumyo series.

    Speed


    Speed means how fast a hone removes metal. Different hones remove metal at different rates according to the criteria used when the stone was designed. Shapton Glass HR stones were designed to cut the wear-resistant Lie-Nielsen plane steel and release fresh, sharp grit easily. They are one of the better choices if you have fully mastered razor pressure and do not put any excessive wear on the razor. Other stones like the resin-based Naniwa Superstones are a bit slower but tend to polish more, probably because of the grit shape and binder.

    A good hone needs to have the right amount of grit in it to cut properly. If all I wanted was to make the cheapest hone, the first thing I’d do is cut the expensive abrasive by 50%. Or 75%. One issue with new folks selecting hones is that they all pretty much look the same. But they’re not. Avoid the cheap eBay and Amazon stones unless it’s simply all that you can afford, and if you can afford these you can easily afford film.

    With Japanese naturals, speed is determined by the hardness and grit content, which is of course variable between stones. Speed can be increased with the use of slurry, generated by a slurry stone (a tomonagura). The same is true of coticules, Thuringians, and synthetics though you may or may not like the results depending on many other factors.

    A good example of the effective use of a fast hone is in bevel setting. The normal grit used by most people is 1k, and the Naniwa Chosera is a common choice. My normal bevel setter is a 2k Shapton Pro and a 2k Shapton Glass HR would probably be faster than the Chosera 1k and leave finer scratches for the next hone to remove. For minor edge correction and bevel work on very hollow razors, a Shapton Glass HR 4k works
    well. The reason that you want a fast hone for use with very hollow razors is that you can’t push very hard on them or the edge will flex and the bevel will round and not develop properly.


    Synthetic vs natural

    Advantages of synthetics are that they’re all the same within a brand and model, they’re relatively cheap, especially compared to some natural stones, and that can be had in grits up to about 0.5 microns. If you’re honing professionally, the ability to replace a stone with one just like it when one wears out is significant, though a hard jnat used only for finishing may last longer than a lifetime.

    Advantages of naturals are that many produce an edge that shaves more smoothly than synthetic edges, though the difference may or may not be significant to any particular user. Naturals can be had in far more sizes (and shapes).


    Barber Hones

    These are vintage synthetic stones intended for barber’s use to keep razors shaving without much time invested. They’re usually fairly small, say 2” x 5” and they tend to be very, very fast cutting. They can be used dry, with lather and other lubricants as recommended by the manufacturer. Most are quite coarse, depending on a burnished surface to provide a fine enough scratch pattern (that grit shape thing again). If you get a ‘good’ one, they can maintain an edge but I don’t know of anyone who would choose one over say, a Naniwa 12k.


    Film


    Film is a plastic film that’s abrasive attached to it and it’s used in sequence to polish the ends of fiber optic cables. You need a dead flat substrate for it like lapped granite or plate glass, and you can put things under the film like copy paper to add a little ‘give’ to the surface to convex the edge slightly and give a supposedly milder edge. There are literally hundreds of articles and posts on film, so I’ll leave it there, but if you’re looking to hone on the cheap or just to see if you like to hone, film is an excellent choice.
     
    Last edited: Jul 19, 2018
    RyX, Edison Carter, Keithmax and 2 others like this.
  2. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    Fix the attachment, and this is sticky worthy, imo.
     
    Zykris, Edison Carter and Steve56 like this.
  3. Steve56

    Steve56 Well-Known Member

    There isn't actually supposed to be one here, I don't know what I did. I'm kind of a noob at positioning attachments. I could resort to HTML but no telling what would happen!

    Cheers, Steve
     
    Edison Carter and PLANofMAN like this.
  4. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    Zykris and Steve56 like this.

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