Hammers to Use With Chisels Part 2 – Hammer Faces

Beware the Jabberwock, my son!
      The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
      The frumious Bandersnatch!

Lewis Carroll
375gm gennou by Kosaburo with a black Persimmon handle resting on a Go board. The head is a classical style seldom seen nowadays.

This is the second post in our six-part series about hammers to use with our chisels. As with all the tool-related articles we publish, this one is based on past communications with, and in response to direct questions from, our Beloved Customers. We hope that not only our Beloved Customers (may the hair on their toes never fall out) but our Gentle Readers too may gain something from these articles.

We sell limited quantities of hand-forged professional-grade chisels to professionals who use them to please their customers and feed their families. We are tickled pink when amateurs purchase our products, but our target customer is the experienced professional woodworker. If you do your part our chisels will provide faithful, reliable service until, after many decades, nothing is left of the blade but a nub. But to make that possible, and to avoid smiles turning upside down, we insist our Beloved Customers use flat-faced hammers to motivate our chisels as a condition of our warranty. It’s that important, at least for the professional that uses his chisel even after the blade and handle become hot.

In the previous post in this series we looked at the Japanese gennou hammer with its two faces: one domed and the other flat. In this post we will examine these two styles of hammer faces in more detail. We will leave waffle-faces to the Belgians for now.

The Domed Hammer Face

Few people in industrialized countries outside of Japan have any experience with flat-faced hammers since manufacturers automatically grind a convex or domed striking face on their hammers. It’s simply what consumers are accustomed too. But I daresay few have ever considered the ramifications of the domed face.

1920x1080 Wallpaper hammer, nails, wood
An average-looking hammer. But is the shape of the domed face uniform, or is it skewampus or tilted? Is the centerpoint of the face and the center of mass of the head in-line? Good luck figuring it out.

A domed face on a hammer has some advantages. For instance, when one needs to “set” a nail with it’s head just below the flat surface of the piece of wood into which the nail is driven. But does a domed face help the hammer drive nails faster or straighter? Does it help reduce the ratio of bent nails to straight nails? Does it motivate chisels more efficiently? No, no and no.

Does this domed face look perfectly centered to you? Does it looks smooth? Can it be improved?

Another more questionable feature of the domed face (depending on your viewpoint) is that it makes it difficult to judge the accuracy of the alignment of the dome’s centerpoint in the face and with the centerline of the hammer head. Who, praytell, profits from this ambivalent construction? I’ll give you one guess, and it ain’t me or thee.

Indeed, if your working hammer tends to bend a lot of nails, I recommend you carefully examine its face with a square for center and uniformity. “Doh! (palm to forehead). No frikin wonder,” may well be your genteel reaction.

So why is a domed-face hammer a problem when striking Japanese chisels? Simply because a domed face tends to focus the impact forces on a relatively smaller area on the wooden handle than a flat-faced hammer does accelerating the wear and shortening the life of the handle.

In addition, and especially if you are skilled at hitting the handle dead-center a high percentage of the time, a domed face will actually cause the crown to try to jump off the handle and to become beaten up, sometimes even dangerously deformed, eventually damaging the handle.

The Flat Hammer Face

You can easily modify a decent-quality, properly-hardened hammer to have a flat face by simply abrading it with a grinder or sander.

Be sure you make the new face planar (flat) and truly square to the hammer’s centerline because a tilt to the left or right will make doing precise work inexplicably difficult and may lead to insanity. I once knew a frugal carpenter (read “cheap jackass”) who insisted on using a hammer with a skewampus face. The cumulative corrosion to his confidence caused his wits to wander into the weeds. A sad but common story, I fear.

If you are modifying a standard hammer with a standard handle, you may want to tilt the face’s plane a bit inwards towards the handle, but there is not adequate space in this post to discuss this modification in more detail.

Be especially careful to avoid overheating the hammer’s face while grinding/sanding it: too hot and the temper will be damaged softening the hammer’s face and ruining it. Seriously. Even a wooden chisel handle will eventually mushroom a steel hammer that has lost its temper. Here’s a guideline: If the hammer’s face becomes becomes too hot to touch with your bare finger, the temper is at serious risk.

Finally, once the face is as flat and square and smooth as you can make it with your grinder or sander, be sure to polish the face because a smooth face wears out the chisel handle slower. A final polish with 320 grit W/D sandpaper is adequate. We polish ours even finer on sharpening stones. Overkill? Yup. Why bother? Because we like purty hammers. Don’t worry, the polish won’t make the hammer face slippery.

By the way, once you have your flat-face hammer, try driving nails with it. You will find it works a lot better for everything except setting nailheads below the board’s face. A nailset works better for that job anyway.

We hope our Beloved Customers will take this article to heart for the sake of their chisels.

Summary

In this post we reviewed two types of hammer faces: domed and flat. We also considered the advantages and disadvantages of each, and explained why a flat face is best for beating on Japanese chisels, and gave an example of the brutish damage a domed face can inflict on a poor innocent chisel. Like me, some of you may have shed a tear at the sight, but I bid you take heart because we also instructed you in how to convert a common domed-face hammer of any sort to a more genteel and polished flat-faced hammer at no cost, one that will also drive nails better. O frabjous day! Callooh! Callay!

To motivate chisels efficiently, the hammer must not only have a flat face, but it must be of the appropriate weight. Of course, the harder the wood, the deeper the cut, the wider and heavier the chisel, the heavier the hammer needed. But what is an efficient hammer weight? We will examine some options in the next post in this series. Please stay tuned, my beamish boys.

YMHOS

A hand-forged square gennou head by Hiroki with a handle made from a traditional Japanese handle wood called “Kamatsu” (Pourthiaea villosa) meaning “sickle handle, also called “Ushikoroshi (“cow killer”). Despite the appearance, the head is one-piece of uniform steel, not a jigane body with forge-welded steel faces. BTW, if someone tells you that hammers with forge-welded faces are superior, direct them to the closest legal marijuana dispensary so they can maintain their waking psychotic dreams.

Other Posts in this Series:

Part 1 – Hammer Varieties

Part 2 – Hammer Faces

Part 3 – Hammer Weight

Part 4 – The Chisel Cha-Cha

Part 5 – Rhythm & Song

Part 6 – Hammers & Health

If you have questions or would like to learn more about our tools, please use the questions form located immediately below. Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google or incompetent facebook and so won’t sell, share, or profitably “misplace” your information.

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