This page has some summary tips regarding the “unicorn” method, which is simply described as a modification of tip geometry in front of a shallower cutting bevel. The tips are added just as a bullet point discussion of certain things that make a difference in results. The True/False style points are added to address things that I’ve seen from gurus or others asserting what the method is or isn’t, and they’re quite often wrong.
I think there’s plenty of space in woodworking for pondering, but there are a few gurus, including folks on forums, who like to speak for others or assert things that are substantially incorrect. It’s not my job to Karen (or is it Ken?) everything, but I’ll carry the murse when it comes to the Unicorn and Cap Iron topics.
Helpful Tips
- Buffer wheel condition – keep it free of a shiny solid glaze. When you start, the wheel will have little strings everywhere and little charge in the fabric. The strings do nothing bad but can be removed if they whip you. When you begin to build a shiny layer of glaze on the buffing wheel, though, it needs to be removed with a brush comb or a piece of thin steel stabbed perpendicularly into the wheel briefly.
- Speed and Fineness – a faster wheel generally provides a better result. The slower the wheel operates, the steeper and shorter the bevel. Similarly, chasing too-fine abrasive while attempting to round the tip of an apex will lead to a short and stubby bevel that works less well than one shown in the microscope picture. Enough speed and enough cutting power (up to 5 micron compound) will yield better results.
- Dirt from the Wheel – the wheel will make a small radius of dirt/wax. It won’t make airborne particles so much, but if you have a super tidy workspace, observe where it goes. This is one of the reasons I like having the buffer on the floor.
- Remove the Buffed Edge with Each Honing –if you are lightly buffing to remove a wire edge only after sharpening, this doesn’t matter. If you’re giving the edge the full treatment, then you need to start with a fresh shallow bevel each time. This shouldn’t take long. Failing to remove the rounded over edge will lead to a progressively steeper or more blunt edge and dullness.
- Use the lower angle – The secondary angle that is illustrated is something over 20 degrees, but certainly nothing close to approaching 30. if you want to maintain a steeper bevel for reasons that I can’t really gather too much, then buff only lightly. Buffing the edge you would’ve used already and doing so heavily will just result in a blunt edge.
- Adjust for Wood – this is just a basic sharpening concept. If you are working very light white pine, you’ll have little luck with a typical honed edge that holds up well in hard maple. If you find the unicorn treatment results in some crushed fibers in really light woods, do less buffing. The fact that the wood is that light lets you know it won’t need that much bolstering.
Q/A or True/False Responses to Assertions I’ve seen
First, for all of the assertions that I’ve suggested inventing anything (cap iron, buffing tips of tools, whatever it is), that’s all nonsense, and it’s peddled generally by a group of folks who intentionally make up nonsense. I don’t know if they are ill or just interesting in stirring others’ pots because they have a lifetime of putting nothing in theirs. Nobody invents much these days, but nonsense is rarely discouraged by fact.
What I will do is figuring things out, distill and then specify. Publishing a method to make double iron wooden planes, talking about the cap iron and how to set it and the myriad of heat treatment and sharpening discussions are that.
I do find this kind of character nonsense annoying, but it’s the goal of the folks peddling it because of a lack of something that has nothing to do with woodworking. What can you do? On to the statements:
The Unicorn is Just Buffing on Both sides of the Blade – False. Actually, twice. It’s using the buffer to hone on the bevel side of the blade, only at the very tip of a tool. You can “just buff” both sides of a blade without issue. It’s not the same thing, and buffing the opposite side of a chisel may not be what you want in the first place.
The Unicorn Method is Just for Cheap Tools – False. I know why this conclusion is made – it improves edge holding, and it’s easiest to see the incremental improvement on cheap tools. However, it improves edge holding on all tools. When applied properly, the method can make cheaper tools outperform “flat honed” more expensive tools. More expensive tools underperforming cheaper tools isn’t a great steady state.
Resharpening is Unpredictable – False. There’s one specific guru who likes to take anything you specify and run with it. And then start making declarations. One of these early on was related to sharpening plane irons (addressed separately). The same guru describes how resharpening becomes hit or miss, which doesn’t make sense. the method starts from the same secondary bevel and then buffs the bevel the same way every time. Failure to refresh the secondary bevel properly can lead to problems, which is why the method involves honing to a burr on the bevel refresh.
The Method Can’t be Used on Plane irons – False. Same guru, same issue. You can buff the bevel side of a plane iron or more lightly buff the bevel side and buff the back of an iron. It is a little harder to get the hang of things with plane irons because too much buffing limits clearance to a degree that it causes problems. So, you learn to buff without doing so much that you cause problems. When this assertion was made, that it couldn’t be done consistently, I made a Youtube video sharpening 7 different types of plane irons and then demonstrating their use. I suspect a lack of touch and discretion is the cause. This is a core thing for all woodworking. If you can’t do a method, then perhaps do a different one. It’s OK. Warren Mickley once responded to someone on a forum “there is a difference beetween it can’t be done and you can’t do it”. I can’t be a lawyer – I swear. I’d be a terrible administrative assistant, too. Some people are really good at both of those. I admire them rather than trying to speak on their behalf.
The Method Can’t be Used on Bevel-Up Plane Irons – False. I find that a heavy dose of the buff on the bevel side of a bevel-up plane iron results in better performance than a flat bevel. The effect of the buffing is similar to adding 5 degrees in steepness if tearout mitigation is an issue. This is *really* forgiving because you don’t buff the flat side of the iron and there’s no clearance issue. Works great both on steep bevels and for shallow bevels (to plane end grain).
Of Making by Hand with Wood and Steel 