I’ve just posted a short video on the machine and hand processes that go into making a pair of Crucible dividers. You can check it out here if you like.
— Christopher Schwarz
Clinching Nails
This is an excerpt from “The Joiner and Cabinet Maker” by Anon, Christopher Schwarz and Joel Moskowitz.
Clinching (sometimes spelled “clenching”) is when you drive a nail that passes through both thicknesses of wood you are fastening. The tip of this nail sticks out about 1/4″ and is bent over and driven into the wood.
Clinching adds remarkable strength to a joint. A 1948 study by the U.S. Forest Products Laboratory concluded that clinching can increase the holding power of a nail between 45 percent and 464 percent – depending on a variety of factors, including the species of wood and its moisture content.
Also interesting: The study concluded that bending the tip across the grain increased the holding power by 20 percent compared to a nail clinched along the grain.
But how do you best clinch a nail? There are several methods.
Four Ways and a Trick
Here’s how automated clinching machines do it: They fire a nail in at an angle, and there’s a steel plate waiting for the nail’s tip when it emerges. When the nail hits the steel it bends over into the wood – essentially it ricochets like a bullet or pool ball.
I’ve never tried this with a pneumatic nail gun, but it sounds like fun on a Friday afternoon.
For the hand clinchers, there are at least two common techniques. The first one is to first drive the nail through the work. Rest a steel plate, anvil or a second heavy hammerhead on the nail’s head. Then tap the tip of the nail with your hammer. It will curl over. Then you can drive the drooping tip back into the wood.
The second technique is similar to the machine process. You drive the nail through the work and against a waiting “bucking iron,” which curls the tip and forces it back into the wood.
There’s one more technique I’ll sometimes use when I’m being really, ahem, retentive. I’ll drive the nail through. Then I’ll use needlenose pliers to bend the tip to the angle I want. Then I’ll drive it into the work. This results in a tidy appearance. I admit it’s a bit much.
When I have a lot of clinching to do, I’ve found that a cast iron table saw wing can be your best friend when clinching at work – doors, lids and the like. Lay the cast wing on your bench and you have a nice big area to support your work as you merrily clinch away. And no, the clinching does not really mar, crack or otherwise defile the cast iron wing.
— MB
The Palm, the Ban Qi and “The Young Mechanic”
Several commenters to yesterday’s post about the origin of the Chinese planning stop, known as the palm, offered some additional information and a Western version.
In the wheelwright’s shop shown in the 12th-century scroll “Qingming shanhe tu” we see a palm at the end of the bench. It is made of two pieces of wood nailed to the bench.
The palm was later known as the Lu Ban qi, or Lu Ban’s wife, because the palm was the brilliant idea of Lu Ban’s wife. (Not to mention she no longer had to act as the planing stop or sustain injury when Lu Ban got a little crazy with the planing). Ban Qi is still used as a term for a planing stop. A modern version of the V-shaped palm is below and is adjustable.
A Western planning stop with similarities to the palm comes from “The Young Mechanic” by James Lukin published in 1872:
Another version using two pieces of wood and wedges to secure the work piece:
My thanks to our readers for joining the discussion and offering more ideas!
-Suzanne Ellison
Origin Stories: The “Palm” or Planing Stop
Lu Ban, born some time between 770 and the 5th century BC, is the divine protector of Chinese carpenters and artisans. He is credited with inventing the basic tool kit of the carpenter and the rules, measurements and rituals associated with building construction. He and his wife* are featured in many Chinese folktales. One story, as told by the Bai ethic minority of Yunnan Province involves how the palm, or planing stop, was invented.
The Origin of the “Palm”**
When Lu Ban needed to plane a piece of wood he would call his wife to come and hold one end of the wood with both hands. She would use all her strength to hold the wood steady. But this was not a good way to evenly plane the entire piece of wood. Too light a hand and the wood would not be smooth and too heavy a hand and the plane would run into his wife. Once, Lu Ban’s strength on the planer was too heavy and the head of the plane hit his wife in the chest, the blade cut her hands and she was pushed to the ground. Lu Ban dropped the plane and rushed to help his wife.
Lu Ban’s wife sat dazed on the ground gazing at her bloodied hands while Lu Ban fretted and did know know what to do. His wife suddenly smiled and realized what she should do. She got up, grabbed a saw and cut two pieces of wood in the shape of a palm. Next, she nailed the pieces on the bench top. She had Lu Ban place the wood to be planed between the two pieces to hold it steady and there was no longer any need for a person to hold the wood while the carpenter used the plane.
Lu Ban admired this idea of his wife and he called the two pieces a “palm.” Later, carpenters changed from wood to iron but still called this invention a “palm.”
Finding the “Palm”
I asked Chris if he could visualize the palm and he suggested placing your hand palm-up (that was the bench surface) and bend four fingers pointing towards the ceiling (the stop). But that configuration didn’t help me see a “palm.” Many images of the low Chinese workbench are hand-drawn and do not show a huge amount of detail. So, the next step was to check through the images I already had and also look for new ones.
The Arrowmaker has a planing stop, but it doesn’t look as though it would be termed a “palm.”
Four benches but no “palms” here.
In this 20th century Chinese comic strip Lu Ban’s wife nails what looks like a doe’s foot to the bench. The doe’s foot, a work holding appliance, is featured in Plate 14 of the forthcoming “Roubo on Furniture” and you can read a blog post Chris did about using one here.
The notch in the doe’s foot seemed to be closer to what the “palm” might look like. The answer came from “Qingming shanhe tu,” a scroll done with ink and brush by Zhang Zeduan during the Song Dynasty in the first quarter of the 12th century. The scroll is 25.5 cm high, 5.25 meters long and is in the collection of the Palace Museum in Beijing. The scroll shows the gatherings for the Qingming celebration in a vibrant riverfront city. The image at the top of this post is one of two where a woodworker’s bench can be seen.
In a short passage in a book about 15th-century Chinese carpentry there was mention of a wheelwright’s shop in the scroll and whether the workman at the bench is using a drawknife or spokeshave.
Find the large tree just off center in the scene above. The wheelwright’s shop is just to the left of the tree and partially under an overhanging roof.
Given the large size of the scroll the scene is too small to discern which tool is in use but what can be seen is the workman is pushing the tool as evidenced by the V-shaped wooden ‘bench stop’ nailed to the end of the bench. This ‘bench stop’ is called a “Lu Ban qi” which translates as Lu Ban’s wife. As Lu Ban’s wife knelt at one end of the bench she held her hands on either edge of the wood. Placed together her hands would form a V. This is the “palm.”
*In the folktales of the Bai Lu Ban’s wife is not given a name, but in other stories she is called Yun.
**This story is based on a Bai folktale translated by Jessica Marinaccio for her thesis for a BA with honors in Chinese at Williams College in 2006.
–Suzanne Ellison
Free Download for Halloween: The Coffin Chapter
If I had to guess, I’d say my wife’s favorite projects of mine are the coffins I built for “The Anarchist’s Design Book.” One coffin ended up at Raney Nelson’s place (it’s where he sleeps, I think). One ended up on the wall in our TV room and holds my vinyl records. And the third is in the basement and is trotted out for Halloween.
Lucy, my wife, adores Halloween.
Building a coffin is great fun, whether you are making it for yourself and your final remains (as I did), to use as a liquor cabinet/vinyl record cabinet or yard decoration.
For fun, here’s the chapter on building a kerf-bent coffin from “The Anarchist’s Design Book.” It’s in pdf format. No DRM or any garbage. Just something fun to read and try.
— Christopher Schwarz