Sharpening Part 11 – Supernatural Bevel Angles

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Pixie, kobold, elf, and sprite, All are on their rounds tonight; In the wan moon’s silver ray, Thrives their helter-skelter play.

Joel Benton

Iron Pixies

Gentle Reader, have you ever placed a tool down, only to later discover it has vanished into thin air? Do your tools ever become inexplicably dull or corroded within what seems like just a few days after cleaning and sharpening them? If so, you may have an Iron Pixie infestation without realizing it. 

Respected fairyologists theorize that, unlike their timid brethren frolicking in forests, or their blingy cousins infesting Hollywood, New York, and Washington DC who delight in tricking the mass media, film industry and corrupt politicians into constantly making greedy, immoral, hypocritical fools of themselves, Iron Pixies (genus Fatum Ferrum), do not fear iron or iron alloys. Indeed, besides pilfering and concealing tools that contain iron, they love nothing more than to use their corrosive powers to return this metal to its natural state through the thermodynamic chemical process known as “rubeum, et conversus abibo” (turn red and go away).

These piratical pixies become especially joyful if the owner of the snatched tool is unable to find it after much frantic searching and is eventually forced to buy a replacement. Only when they see the replacement tool will the pernicious pixies permit the owner to locate the pilfered tool, usually rusty and chipped.

We’ll come back to the supernatural impacts of these little monsters on woodworking tools, but first let’s examine some more mundane details about sharpening blades, and a few things that typically go wrong with them.

The Ideal Bevel Angle

There is such a thing as an “ideal bevel angle” for each blade in each cutting situation, one that cuts the wood quickly, cleanly, with minimum force expenditure and that keeps the blade effectively sharp for the maximum amount of cutting possible, but determining this angle is not an easy calculation since it is difficult and expensive to actually observe what is happening at the cutting edge from a shaving’s-eye-view.

For example, a steep  60° bevel angle on a chisel will support the cutting edge thoroughly and will be durable, but it will pound the wood more than cut it wasting time and energy and damaging the wood unnecessarily. On the other hand, a 15° angle will cut well, but is likely to chip and dull quickly. A balance is necessary.

This balance will depend on many factors including hardness and abrasiveness of the wood you are cutting at any time (e.g. Sugar Pine versus Ipe), the quality and nature of your chisel blade, the type of cut you are making (low-pressure surface paring versus high-pressure deep mortises), and the care you take to protect the cutting edge. Yes, technique matters.

Determining the ideal bevel angle is ultimately a trial and error process the diligent craftsman will unconsciously perform until it is second nature, but the following are some general guidelines to get you started.

Most Japanese woodworking tools, including plane blades and striking chisels (oirenomi, atsunomi, tatakinomi, mukomachinomi, etc.) perform well in most construction and furniture woods with the standard 27.5°~30° bevel angle. This is a good compromise, acute enough to cut most wood efficiently without too much friction, while still providing adequate support to the thin cutting edge to avoid chipping. 

But like any rule, there are exceptions. For example, 35° is often a superior bevel angle for chisels when quickly cutting mortises in harder woods or planes shaving tropical hardwoods.

When cutting very soft woods, such as Paulownia, similar to balsa wood, a 22~24° bevel angle may work best. 

Paring chisels (tsukinomi), when used properly, are subject to less violent forces than striking chisels, and can easily handle a 24° bevel angle. But for most woods, a professional-grade Japanese plane or chisel blade will likely experience chipping if the angle is much less. 

There are many variables and potential solutions one might consider, but as a general rule, your humble servant recommends starting your experiment with a 27.5~30° bevel angle for plane and chisel blades.

If Beloved Customer finds that your blade chips or dulls quicker than you think it should, increase the angle gradually until it calms down. This can result in a double-bevel blade, one difficult to sharpen freehand. In this case, your humble servant fully supports using a honing jig, at least until you achieve a flat bevel wide enough and stable enough to sharpen freehand. But don’t handicap yourself by relying solely on honing jigs because they can become like training wheels on a bicycle: slow, awkward and childish.

Mercurial Bevel Migration

There is a strange, almost supernatural phenomenon many woodworkers experience, the first evidence of which is a plane or chisel blade that previously held a sharp edge a long time suddenly and inexplicably beginning to dull, roll or chip sooner than before. Even professionals with many years of experience occasionally see their tools exhibit this nasty behavior. 

Some craftsmen faced with this despicable dilemma begin to question their sanity. They may ask themselves: “Has heaven turned its face against me? How do I rid myself of this curse? Do I need to see a shrink?” Other craftsmen, more aware of the dangers of pernicious pixies, draw strange hex symbols on their walls or inlay brass circles and pentagrams into their floors to exorcise them from their workshop. Indeed, this practice has a long history in Europe and America.

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Unfortunately, more than one blacksmith has been falsely accused of poor workmanship when the fault actually lay with the tool’s owner unwittingly allowing Iron Pixies to run amok. If this happens to your tools, please use the methods described below to purge any pestilent pixies in the area.

Gentle Readers and Beloved Customers would be wise to consider all possible causes of Mercurial Bevel Migration (MBM), including those unrelated to any infernal fiends that may or may not be skulking in your lumber stacks.

But if not pesky pixies, what else could cause this maniacal metallurgical malfeasance?  Never fear, Beloved Customer, there is another possible explanation, one that can be resolved without paying for years of expensive psychotherapy and mind-altering drugs, placing small bowls of blood and milk around your workshop, enduring the pain of tattoo needles, paying for stinky ceremonies involving burning sage and spirit drums, or even the simple ritual described in the postscript below.

The more likely cause is simply that it’s human nature when sharpening chisels and Japanese blades with their laminated, top-heavy construction to apply more pressure to the bevel’s rearward half (farthest from the cutting edge) abrading the softer jigane body more than the harder hagane cutting layer. Eventually, as the soft jigane wears away, the bevel angle will decrease to the point where the cutting edge loses support becoming fragile.

Once you are aware of this tendency and take preventative measures (and assuming you don’t have an iron pixie infestation), all should be well.

Next let’s examine some measures to get rid of both this bad habit and trixy pixies.

Pixie Predation Prevention & Pacification

If you suspect the presence of iron pixies, you should perform the Covington Pixie Detection Test (CPDT). A reliable method is described in the next section below.

In any case, and because prevention is better than Ritalin, you should create a workshop environment unfriendly to pixies. The following is a partial list of measures I have found to be effective.

Image result for brass bench dog
Brass bench dogs are an effective pixie repellent
  1. Cleanliness: Clean bench surfaces and sweep the floors daily. Vacuum and wet-mop workshop floors at least twice a year during the winter and summer solstices (approximately June 21 and December 21);
  2. Add more lighting: Iron Pixies fear light because it reveals them to their enemies;
  3. Keep a pair of boots near the door into the workshop: Pixies are deathly afraid of boots (but not steel-toed boots), especially when they contain the feet of sharp-eyed human children, but just the sight of boots will prevent them from entering a space;
  4. Keep brass benchdogs in your workshop. Expert fairyologists insist, and I agree, that having a brass bench dog (remember, Iron Pixies do not fear iron or steel or the IRS) or two close by will banish Iron Pixies to the workshop’s dark recesses and keep their nasty claws away from tools. The deterrent effect of bench cats is unclear, but if you decide to rely on one, be sure it bothers to stay awake;
  5. Welcome spiders: Although this may seem to contradict No. 1 above, Iron Pixies fear spiders, especially daddy longlegs, who delight in tangling them in their webs and tickling them to expiration.
  6. Make regular offerings to the gods of handsaws. More on this subject in future posts.
Richard Kell bevel gauge
A compact and effective brass bevel angle gauge by Richard Kell

A more mundane but sure way to prevent MBM is to make or buy a bevel angle gauge and regularly use it to check your bevels during sharpening. Aluminum, stainless steel or even plastic gauges will work of course, but brass or bronze are more effectual at purging perfidious predatory pixies because copper is toxic and zinc causes pixies indigestion. Be sure to store it close to your valuable steel tools to help repel the maniacal little monsters.

Here’s the important thing: once you have this tool in hand, use it to check each blade during sharpening to ensure you are maintaining the correct bevel angle instead of allowing it to decrease incrementally over repeated sharpening sessions. Make this a firm habit. More on this important subject in future posts.

Remember to measure the bevel angle at the blade’s far right or left edges because the hollow-ground ura of Japanese blades makes it difficult to correctly measure the angle if you check it elsewhere.

Pixie Detection Methods

A serious pixie infestation in a toolchest located in a clothing-optional workshop. Notice the absence of bench dogs, brass bevel angle gauges and boots in this image. An invitation to disaster!

Iron Pixies are secretive creatures most people never see, but if you suspect you have an infestation, a detection test is called for.

While there are many proven methods to test for pixie infestation, the least expensive non-toxic method to test for pixie infestation is the Covington Pixie Detection Test (CPDT). The execution is simple, but it requires some skill and confidence in one’s abilities.

To the perform the CPDT, sharpen a plane blade, and while doing so, attempt to “stick it” on the stone as shown in the photo below. This phenomenon is evidence the stone and the blade are in such perfect contact that the suction between the blade, water and mud on the stone’s surface strong is enough to support the weight of the blade. It can only be achieved when localized sources of natural chaos, of which iron pixies are a prime example, are under control.

No, this is not a trick photo with concealed supports, superglue, or photoshop enhancements. The blade is “stuck” to the wet stone’s surface. This is a rite of passage those who wish to become proficient in sharpening must eventually accomplish, iron pixies or no. Not recommended for potato chip-thin Bailey-style plane blades.

Assuming your blade, stones, and skill level are up to the task, if you are unable to accomplish this marvelous feat even after many attempts, the likelihood of an infestation of peevish pixies nearby is high. In that case, use the preventative measures listed in the section above, or the banishment ritual described in the postscript below. You should also flatten your sharpening stones (especially the rough and medium grit stones) and make sure your blade’s bevel is perfectly flat. Bulging bevels are the pernicious pixie’s playground. (Aha! Iambic pentameter!)

Fair warning: If you stubbornly persist in your efforts to “stick” a plane blade before purging the area of pixies, they may go berserk to prevent this sublime event from occurring. If that happens, Katy bar the door!

Infernal Pixies! You Shall Not Pass!!

In the next stage of our adventure, we will examine some of the health ailments blades commonly suffer.  High cholesterol in chisels? Planes with pneumonia? Or just toolish hypochondria? Stay tuned to find out more.

YMHOS

Postscript: Pixie Catch-and-Release

A few tender-hearted Gentle Readers, sick and tired of their precious tools rusting and being stolen, have asked your humble servant for advice about live-catching the Iron Pixies scuttling around in the dark and dusty places of their workshop and then release them back into the wild. I can only share my meager experience.

While the concern these Gentle Readers have for the welfare of natural creatures is laudable, it is decidedly misplaced because pixies are not natural creatures like squirrels, robins or even tax collectors. (There are some who contend the later are closer to trolls than natural beings, but that is a scurrilous rumor promulgated by tax accountants.) But I digress.

Gentle Readers should note that Iron Pixies are not natural beings, but rather supernatural creatures from the land of Faerie that choose to leave their native plane of existence to inhabit workshops in our mortal world for the simple malevolent joy of ruining iron and steel tools. As mortals, we may catch them and we may crush them, but few have the ability to banish them entirely from our world, contrary to the claims of The Learned Society of York Magicians, the only documented exception being Mr. John Uskglass and perhaps, it is rumored, an obscure magician named Mr. Jonathan Strange.

My point is that, since we mortals have no access to the supernatural environment from whence pixies hale, we cannot “release” them back into their natural environment, but can only strive to make our workshops less pleasant places for them to pursue the mischief they love.

Your humble servant has not researched all methods of capturing pixies and so can offer no certain advice. However, if you are determined to design and deploy such a live-trap, remember that iron pixies are exceptionally clever and can easily avoid and certainly destroy most any trap, especially if it has metal parts.

Bench cats have been known to frighten pixies away, but most are too lazy. And no matter how you cook them, and regardless of what hot sauce you use, iron pixies always taste like old garbage dumpster wheels and are almost as hard to chew, so scrumptiousness is never sufficient incentive for our feline masters.

I have experienced moderate success banishing iron pixies from my humble workshop, at least temporarily, using a combination of the techniques listed above and some ancient magic.

To perform a pixie banishment rite, you will need at few things, chief of which are at least one small, quick, sharp-eyed, strong-lunged child that still believes in Santa Clause, and a pair of large, worn, leather work boots. Never steel-toed boots, mind you, no steel at all!

Open one door leading directly to the outside just a crack. Not too far, only 1~2 inches.

Help your sharp-eyed child put the boots on their little feet in your workshop where the pixies can observe, being sure the boots won’t fall off.

Direct said child (or children) to march around your workshop in three circuits widdershins (counter-clockwise) while stomping their boots loudly and screaming “Pixies Flee!!”

Have each circuit end at the partially-open door whereupon each child should toss a small piece of steel or iron, such as a nail, screw or nut, through the opening while shouting these same spells. Most children have loud voices indeed when they choose to use them.

The more children the better. You may need to borrow boots from friends and family. Don’t forget the Santa Clause thing.

You should lead the way and set the example, of course.

Nothing scares pixies as much as small children stomping close by in big boots while screeching loud magical commands. Seeing iron or steel then fly through an opening to the outside will usually drive them out.

A word to the wise: Incentive must be provided to the child (or children) if the ceremony is to succeed because the workman is worthy of his hire. Chocolate or other sweets work fine. The child’s mother may object to this form of incentive pay, but carrot sticks provide neither sufficient energy nor adequate motivation to small children in my extensive experience. Besides, who ever heard of fruits and vegetables helping magic? Codswallop!

All the same, best to do it when Mom is away if you think she might degrade the ritual through nagging.

Some Faeriologists have suggested that a variation of this ritual is also effective at driving hidden monsters from under beds and out of closets in residences. Indeed, such a ceremony has been an annual traditional ritual in most households in Japan since ancient times.

For banishing monsters from living spaces, open all doors and windows during daylight hours, and, while screaming “Demons Depart!!,” members of the household, including children of course, should toss a handful of dried beans through each open door and window to the outside, closing them tightly afterwards.

This exorcism process is most efficacious when performed on or about February 3rd.

Boots are not mandatory.

Children may be small, but they have an important role in protecting the home and family and your tools too. It’s a father’s duty to let them know it and show them how.

YMHOS

If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

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Links to Other Posts in the Sharpening Series

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