No one should be ashamed to admit he is wrong, which is but saying, in other words, that he is wiser today than he was yesterday.

Alexander Pope

In the previous article in this series we finished fitting and shaping the handle of our gennou hammer in accordance with our design document. Some refinements may be pending the results of testing, but in any case the time has come to attach the head.

This is an important task, perhaps not as easy as it sounds, because this is a craftsman’s handle, made with love and skill, not a mass-produced cockroach killer ground out by barefoot Bangladeshi farmers and secured with crude wedges. It’s not a typical tool of the sort sold at Home Despot designed to fail quickly and be tossed into a landfill soonest. And because the head is not secured with barbaric wedges but relies entirely on the extremely tight fit between the eye of the steel head and the tenon Beloved Customer cut on the end of the handle, some careful, but nonetheless violent action is required to successful connect head and handle. The purpose of the article, therefore, is to help you install it carefully with all due violence.

Installing the Head

Beloved Customer can install the head either before or after sanding and finishing the handle, but in this example we’ll attach the head before testing and finishing the handle. This approach will be most efficient if you decide to adjust or rework the handle after performing the tests I recommend in the next article.

In this case, I use the word “finish” to mean to apply a chemical “finish material” to the wood, not to “complete” the work or “conclude” the job. This difference in definition matters to me because confusion regarding the dual, even treble meaning of the word “finish” has caused problems for me in the past. So there you are.

Preparing the Tenon

First, remove any tape remaining on the tenon and, if necessary, use a solvent such as lacquer thinner to remove any adhesive residue. DO NOT USE soap, water, or any water-based chemical as this will make the tenon swell! After cleaning there should be no finish material, wax, oil or unicorn wee wee left on the tenon.

Depending on the relative humidity the handle is acclimated to, it may be advisable to make an effort to shrink the tenon a bit by placing the handle in a low-humidity environment for a time. Please do NOT microwave your handle, cook it in your oven, or heat it in your toaster, not even with cheese and Tabasco Sauce.

There are several ways to remove moisture from the tenon in order to shrink its width and thickness a bit without ruining the handle or burning down your workshop. Perhaps the safest way is to store it for a time in a tightly-sealed plastic container with packages of silica desiccant. Other ways include placing it in a warm spot close to an operating gas furnace, or indirectly exposing it to an electric room heater for a day or so.

If you use any method that involves heat, make sure you are nearby to monitor progress and deal with scorching and fires.

Orienting the Tenon

You’ve already shaped the handle, and shaved and lightly chamfered the tenon so it should partially fit into the head’s eye almost as deep as the chamfer, but should go no further using only hand pressure.

Please keep in mind during this process that it’s extremely important to get the tenon started in the eye straight, and to keep it straight, without allowing it to become cocked.

It’s also important to install the head in the correct orientation. This usually means it’s flat striking face is oriented towards chisel or nail, and with the brand oriented towards the handle’s butt.

Some people like to orient the head’s brand so it faces up (away from the butt) when using the hammer. I can understand this compulsion, and while it makes no difference in performance one way or the other, you should be aware that it’s seen as bass-ackwards among professionals in Japan.

Starting the Tenon

Of course, in accordance with your humble servant’s advice in previous articles, you’ve already created an elegant dome on your hammer’s butt to prevent these taps and strikes from damaging the handle.

I like to place the head on a working surface such as a benchtop or a softwood board like pine or cedar resting on the floor/ground cushioned by a piece of leather or rubber to prevent slipping.

Insert the tenon into the eye, and, after sighting the handle and head from multiple directions to check alignment, when you are absolutely certain the tenon is poised to go into the eye straight, tap the handle’s butt with a flat-faced hammer, genno (not a domed-face hammer) or mallet. After a few taps, stop tapping, check your progress, and make sure the tenon is going in straight and not cocked.

Although the tenon should not have entered the eye more than a millimeter or two, it should be an extremely tight fit, with each tap making barely any progress.

I can’t describe the sensation in writing, but if the fit is too tight at this point in the process, you may need to scrape or sand the tenon a little.

Driving the Tenon Home

This is where the “violent” part of the job I mentioned above begins.

With the tenon properly aligned and started in the eye, stand up, hold the hammer in a fist with the head hanging straight down, and strike the butt of the handle with your hammer or mallet paying attention to its progress into the eye with each strike and the friction created. Gradually adjust the impact force of your strikes accordingly. Don’t be surprised if it takes literally dozens of extremely hard strikes to install the handle completely. If the tenon just slips in, however, we have a problem, Houston.

If you find that the fit is too loose, however, don’t despair, simply shim it with quality paper as described in the last section of the previous article. Remember, most people find it difficult to get the tenon/eye fit right the first time. Such adjustments to a new handle are nothing to brag about, but neither are they something to be ashamed of. It’s more the rule than the exception until experience is gained.

Some people like to make their tenon extra-long so it projects out of the eye 6-12mm or so. Nothing wrong with this approach, but it looks silly to me in the case of a new handle. Once again, beauty is in the eye of the bean holder.

I was taught that the ideal is for the tenon of a new handle to remain recessed inside the eye a few millimeters. The purpose for this goes back to one of the reasons for the gennou handle design described in this series of articles, namely, that the handle does not have a tumorous swelling below the head but the neck is approximately the same dimensions as the eye for a portion of its length to permit the user to tap the handle further into the eye should it loosen. By leaving the end of the tenon short of the end of the eye in the case of a new handle, one provides visual evidence that (1) the handle is tightly fitted and; (2) that plenty of tenon length is available for making such adjustments.

Accordingly, a tenon projecting a long way out of the eye indicates to the knowledgeable observer that either the handle is either old and has been adjusted many times, or the tenon fit was sloppy from the beginning. In my humble opinion, a tenon of a new handle projecting from the eye a significant distance looks odd, but in practice, it doesn’t make much difference. The choice is yours.

In the next article in this series of articles about danger and violence, we’ll test you’re new handle. How exciting!

YMHOS

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