I explained edge geometry here. Now we’ll examine the basics of how we use hones to create that geometry.
One of the really neat features about the classic straight razor design is that the manufacturers actually set the correct bevel angle for you by creating their razors with approximately a 4:1 blade width to spine thickness ratio that makes the spine of the razor a honing guide for a bevel of approximately 14 to 18 degrees (usually).
This means that laying the razor flat on a hone creates a perfect bevel. This was an ingenious feature when it first became standard and it still is. The most difficult part of honing a knife or almost any other cutting tool is keeping the blade at the correct angle to the hone in order to create the proper edge geometry. By hand, that is very difficult, indeed, and there are countless “honing guides” created to help someone accomplish this with everything from hunting knives to scissors. But with razors, the honing guide is built right into it!
So, always, always, always keep the razor completely flush to a hone when honing the edge. The spine should literally ALWAYS be laid on the hone with full contact any time the edge of the razor touches the stone. If you touch the edge of a razor to a hone without the spine touching, you probably did some level of damage to the edge. This is critically important and should be your very first rule of razor honing. No part of the razor should ever touch a hone unless the spine is already in solid contact.
Hones shape steel through abrasion. Individual grains of abrasive imbedded in or integral to the hone have a crystalline structure that scrapes very small amounts of metal from a blade as the blade is passed across the crystal. If you understand the way a rasp or sandpaper block works on wood then you understand how a hone works on steel. It’s the very same mechanism of abrasion at work.
When sanding wood, coarser sandpaper removes more wood and makes deeper scratches in the wood than finer sandpaper does. You might want to shape your wood with an 80 grit paper. But it won’t leave a very nice finish behind when the wood is shaped. So then you would use finer and finer grits of sandpaper to remove the marks left by the previous sanding with coarser grits. You would continue with finer grits until you have a finish as smooth as you want to have. The coarser the grit, the faster the cutting and the rougher the finish. The finer the grit, the slower the cutting and the finer the finish. Hones and sandpaper…. for all intents and purposes, the same thing in a different form for slightly different work.
To choose the right hone for the job, you have to evaluate the condition of the edge of the razor. If it’s got damage and chips or flattening, you need to create a brand new bevel and a coarser hone of 600 to 1200 grit would work well for that. It will remove the steel rather quickly and abrade away the edge until a new bevel is created. Laying the razor flat on the hone, you slide it across the hone edge first. Make sure the spine is touching the hone the whole time and, of course, make sure the edge is in solid contact, too. If the spine isn’t making contact, your bevel won’t be right. If the edge doesn’t make contact, you’re not doing anything but grinding away your spine.
You will want to remove steel evenly from both sides of the edge in this way with several strokes on one side and matching strokes on the other. You want to apply even and very light pressure to the hone. You should feel it “draw” and cut as you slide the edge along it. You want no more pressure on the spine than necessary. You’re not trying to grind down the spine. That’s just your guide. The real purpose of honing is to shape the edge of the blade, so that’s where the most firm contact should be. It should never be enough pressure to flex the blade even a little bit. Light, steady pressure and strokes gets it done. With experience, you’ll figure out how much pressure you can apply and still get good results.
Once you have achieved a clean bevel on the blade and you’ve got freshly honed steel on both sides of the edge along the bevel meeting precisely with zero radius and zero flatness on the edge, you’re ready to refine the edge. At this point, the razor is already dangerously sharp, but the edge will be still rather jagged with microserrations from the coarser hone. This step, of course, can be completely skipped if the bevel is quite good on the razor. You always want to use the finest grit capable of doing the job with a reasonable amount of effort and time. An edge touchup is always done on a fine hone (8000 grit or maybe more). Only the creation of the initial bevel should be done with anything coarser than that. 600 grit, for example, would be good for a razor that needs some really serious work with microchips and very visible edge deformity where a completely new edge geometry must be ground into it.
Once your blade is sharp, then it’s time to refine the edge with finer grit hones that grind away the tops of the peaks created by the coarser hone as the scratch pattern generated a series of peaks and valleys along the edge at a miscroscopic level. This is the purpose of finer hones – always to grind away the tops of those ridges until all deep scratches are eliminated by grinding away everything above them.
The final goal is to arrive at an edge geometry that is very consistent, has no visible scratches, has zero radius in the bevel and appears polished to the naked eye. If you can see scratches along the bevel with your naked eye, it’s not fine enough to be a good, comfortable shaver.
So, to recap.
Always step up from coarser hones to finer hones once the bevel is established.
Go back to coarser hones, only if you realize you didn’t get the bevel completely reset yet.
Always keep the spine of the razor touching a hone when the blade or any other part of the razor touches the hone.
Make smooth strokes, edge leading, alternating sides of the razor to keep the grinding even.
Once you’ve got a solid and consistent scratch pattern along the entire bevel with the hone you’re using (and the bevel is completely formed and very sharp), it’s time to go to a finer hone.
There are diamond hones, waterhones and oil hones.
All CAN be used dry, but none are at their best dry.
Waterhones are, in my opinion, the best choice for razor honing. Diamond hones are excellent for grinding new bevels. Both of these require water (according to directions) for best results. Diamond hones are often advertised to be used wet or dry, but use them wet. Dry them after you’re done. They’ll work better and last longer.
Barber hones come in a variety of fine grits and I like them a lot. They’re inexpensive enough to pick up a few for your collection and if you use them much, you’ll probably like them. Unlike water hones, they don’t wear away quickly and can be slower cutting because of that. But they need a lot less maintenance and generally create a rather highly polished bevel because of their grit structure. I like using a mixture of water with a good dose of dish washing soap in it. The soap cleans and lubricates the hone as you use it. It will cut much quicker and finish much nicer with this cheap lube method.
Natural stones are great but very expensive. These would not be my recommendation as the first hones for anyone to buy and use, but I like them and they’re really nice to have and use. So, it’s really up to your budget whether you want to plunk the money down for them. If you can afford them, there’s no reason not to get one or more as you become experienced.