When going on a get-together with my friends from university, I occasionally offer to sharpen their knives for free or gratis. For that purpose, I used to take with me my sharpening stone, which initially was all that I had to sharpen knives. With time this has evolved into a kind of traveling sharpening kit and in this post, I will describe its evolution a bit. Let’s start with a picture, followed by less than a thousand words.
©Charly, all rights reserved
I have started with the grey, two-layer silicon carbide whetstone on the left. It has to be soaked in water before use and it is the exact type of cheapo basic coarse/fine stone that my father has used to sharpen knives all his life and with which he taught me how to sharpen knives when I was ten years old. With care, it is possible to sharpen a knife with this stone alone, although not to shaving sharp, for that, stropping is necessary. As an impromptu strop, I have used on my travels either folded paper or a dishcloth with a bit of toothpaste on. It was possible to get knives to shaving sharp that way, but it was a bit laborious and time-consuming.
Thus came the second addition to the set, the beige-red stone. The red layer is of a significantly finer grit than the fine carbide layer on the grey stone, which is better for a touch-up on a knife that is not overly blunted. It is a very hard and not overly porous stone that can be used with either water or oil. I do not know its composition, but it does not behave like carbide and does not soak up water much. I only use it with water, it is more practical on travels.
However, stropping was still a major pita. Luckily, I found my grandfather’s old leather strop for razors when rummaging around in the attic (I found the razors too). It consists of a leather belt sewn into a loop that is spanned with a screw. The leather was rotten, but it was not a lot of work to replace it. I improved the design a bit with a bottle cork cut in half to not span the leather over a sharp edge, which would lead to faster deterioration. I am thinking about making several of these for my shoppe too. This has made stropping a lot easier, although it is not ideal for big knives. It works reasonably well even without abrasive paste – this strop is not primed and I am still pondering whether or not I should prime one side or leave it as it is.
One of my friends has a small folding knife that has a kukri-like blade gomtry. That unfortunately means that it is not possible to sharpen with a flat whetstone that cannot reach inside the tight concave curve of a small blade. A stone with a curved surface is needed. And I found a few exactly such stones when I was visiting my aunt – she lives near a river in an area where quartz cobbles are easy to come by in all kinds of shapes, sizes, and surface smoothness. A quartz cobble does not remove the material as well as a carbide stone does but it does work well for maintaining an edge that is not overly deteriorated. And no, I am not joking – it really is perfectly possible to sharpen a knife properly with a stone found in nature, with a bit of skill and care in selecting the right stone.
The last edition to the hand sharpening kit was a hard-backed strop and a hematite-based stropping compound. The strop is simply a black-locust board with leather glued on both sides and a handle screwed on one end. The leather is with the skin-side out on one side and flesh-side out on the other. The rougher flesh-side out was subsequently primed with the stropping compound. It is hard and big, and thus suitable for stropping even really big knives. It is very efficient too, a few strokes on the primed side and a few more on the clean side, and any knife is as sharp as a razor.
For traveling the stones get packed into a plastic food container with a silicone pad and a few other things like the two wooden wedges with winkles (those were an afterthought this time because I knew I will be teaching someone to sharpen knives and I wanted to have some easy way to demonstrate the right angle) a smaller bowl and a silicone pad.
I think this is the final stage for me, I cannot think of anything else that I could need.
I do wonder whether it would make sense to make all of this into some kind of snazzy “traveling sharpening kit” and offer it in the shoppe. It is not a sharpening gizmo, it does require some skill to use properly.
And if you are wondering what you need to sharpen knives to a truly wicked edge, here is all you really need to achieve that goal and none of it is overly expensive or difficult to make. You can buy fancier or more expensive equipment but you do not need to.
How does your Grandfather’s razor strop work?
It looks like it might be two solid bars with a fixed plate holding the far (not-handle-end) half-cork, and maybe a threaded plate tensioning the near half cork against the far end.
I remember my great grandfather teaching me how to sharpen the blades of my pocket knife with stones found on the river rhine. I have forgotten most of what to look for since then, sadly. I have an identical grey/darkgrey whetstone, but after reading I think I should look for a finer stone like the red one for my scalpel blades. It is pretty amazing, how quick cardboard, foam and other crafting materials dull these blades.
These wedges for getting a good angle are a great idea, I might steal that :).
@davex, you got it right. If I decide to make a few pieces for sale -- I would have to lose money on them -- I will also make a blog post detailing the construction.
@avalus, I think that for scalpels the hard-backed strop would also be great for you if you do not have one already.
Thanks, I’ll give that a try as I don’t have one.
You use what you have. For years I used various grades of good quality wet/dry silicone carbide paper on a hard surface to sharpen blades. My kit fit in a tradesman’s aluminum clipboard that was a couple inches deep. Even had small squeeze and spray bottles for the water. For interior edges I would tape the paper around a glass bottle. For a time I used the thin aluminum of the clipboard as a base but eventually found a piece about 8x10 of 3/8 aluminum plate. The stiffer and flatter surface made better edges easier.
Later I found a deal at a local Goowill on a leather belt from the 60s. Wide, thick and still live I cut it into a couple strops. I used carbide, eventually diamond, valve grinding compounds with the leather.
Had a job where I needed to drill holes in glass and read about chucking a wood dowel in a drill press, forming a pool of putty for the water and diamond grit. The end grain really holds the grit and drilling goes far faster than I had imagined. Taking the hint with the grit in end-grain I made a couple small ‘butcher block’ assemblies and used those to strop/ grind/ sharpen. The end-grain holds the diamond powder so it cuts fast but it is also impossible to clean to change grade. So each grade has to have its own board. It worked so well I lost the clipboard and paper setup.
Moving a few years later someone decided they needed my diamond grit and boards more than I did. So I made do with a cheap two-sided carbide stone. Added ceramic stones, both flat and cone, I bought at a garage sale. Those are rattling around here still but I couldn’t say where.
A couple years ago I inherited a three sided washita stone set. I works.
In pinches I’ve variously used files, available bits of stone or concrete, random orbit sanders, side grinders, the sole of an old boot, and the V-belt on a running pickup truck to get enough of an edge to do a job. As the man said: ‘That which works is good’. Necessity is a mother … Rough and ready construction trades methods to get-er-done.
It’s been a while and I still have sweet memories of the contemplative nature of sharpening at home at my own pace. The satisfaction of an edge that makes the hair jump off with barely a touch.
The other day I saw a syringe full of 2500 grit diamond valve lapping compound and thought it might be nice to recreate those boards. Finest I used to have was 1200 I think. Then again diamond impregnated steel plates are available. And much finer. Perhaps a buffing wheel on that old grinder in the shed. A touch of compound and …. Hmmmm.
You are an evil man. So many other things need to be done and here I am getting moon-eyed and distracted thinking about a new sharpening rig.
@lorn I am one evil weevil indeed.
Using end-grain wooden boards primed with abrasive for stropping the edge has occurred to me too, I did not have the opportunity or need to test it yet though.
One property of hematite buffing compounds is (allegedly) that the particles are easily crushed. Thus its abrasive action is significantly less aggressive than that of modern buffing compounds (lesser rounding off of edges), and one does not need to use a grade of grids for buffing because the abrasive gets finer and finer with each stroke, similarly to what Marcus has described for polycrystalline diamond. I have done some manual polishing and buffing with hematite on the rondel dagger, and I do think that it is well suited for this task indeedy. I will make a leather belt for my belt sander for buffing with this compound specifically and I will test it at some point in the summer. I have zero reasons to expect anything other than good results.