While screw vises were known in Roman times (there is an extant example of one used for jewelry making at Augusta Raurica), they don’t start showing up on woodworking benches until much later. The earliest image I know of is from northern Italy in the early 14th century and shows workers constructing Noah’s ark.
While these vises appear similar to modern vises, there are significant differences. On these early vises, the screw does not move. Instead, there is a movable nut that presses the chop against the work.
These older screw vises are easier to make than a modern vise and can be installed directly into the benchtop without much effort. To make these vises, you’ll need a threadbox and a matching tap. These once-common tools are available used, and it’s worth searching out a functioning set because with them you can make all manner of vises and clamps. I also use these tools to make threaded parts for furniture pieces to allow them to be knocked down flat.
Note that the German threading kit shown in the photos cuts a 1-1/8″-diameter (28mm) thread, which is a good size for general workshop use. The 1″ version would also work fine and allow you to use a store-bought 1″-diameter dowel to make the screws. You can make the vise’s jaw any size you desire, including the entire length of the benchtop. Because I don’t build boats or fear the Great Flood, I made the jaw of my vise (sometimes called a “chop”) 1-3/4″ x 6″ x 36″.
Begin by making the screws. Mine are hard maple, 1.10″ in diameter (which works with the 28mm threading tool) and 12″ long. Turn down 4″ of the length to 1″. This 1″-diameter section will be glued into the benchtop. Thread the remainder of the stick.
Now lay out the location of the through-holes for the screws on the chop. My holes are 30″ apart on centers and located 2″ down from the top edge of the chop. Bore 1-3/8″ holes through the chop at both locations. The oversized holes will allow your chop to pivot and clamp tapered workpieces.
Show the chop to the front edge of the benchtop and use your 1-3/8″ bit to punch centerpoints on the front edge. Drill 1″ holes that are 4-1/4″ deep into the benchtop. Glue the screws into their holes.
Make the nuts from maple. Before wasting time on shaping the nuts, bore and tap several holes in a board and use the two tapped holes that came out the straightest and cleanest. Cut the nuts to shape using [the figure above] as a guide. Then rasp the corners. Simple screw vises such as this are nice for working on the edges of chair seats, planing the edges of boards or working on anything that needs to be held securely. I have installed them on low benches and tall ones.
When Wilbur Pan was doing his pediatric residency at Children’s Medical Center/University of Texas Southwestern Medical Center in Dallas, he and his colleagues developed a routine. Each Saturday, when they were on call, they’d go through their rounds as swiftly as possible so that the residents who were on call the previous night, and any patients who could be discharged, could go home – as Wilbur notes, no one sleeps well at the hospital, and that includes children.
They were usually done with rounds by lunchtime. Saturday afternoons were generally quiet – they got few kids in the Emergency Room. So Wilbur and his colleagues would “sit around in the residents’ lounge watching college football,” he says.
After the football Wilbur would grab the remote control and switch the TV to PBS “to watch Norm or Roy.” Because they watched “The New Yankee Workshop” or “The Woodwright’s Shop” every Saturday afternoon, they quickly figured out how the episodes typically progressed. At some point during any given episode of “The New Yankee Workshop,” Wilbur recalls, “one of us would say, ‘Hey, I bet Norm’s going to get the dado stack.’ And then Norm would say, ‘I’m going to get the dado stack!’ and we would all high-five each other.” Ironically, he goes on, “none of us did any woodworking.”
What a bunch of geeks.
Today, Wilbur does as much woodworking as he can. He started – or more precisely, started back up – around 2006, after he and his wife, Mary, bought a house in East Brunswick, N.J. After living in apartments for most of his life, it was the first time since high school, when he took a shop class that taught him to make a bellows (which his parents still use), that he had a place to do woodworking at home.
Wilbur was born in Lafayette, Ind., in 1964. His parents had emigrated from China to Taiwan in the late 1940s, and from Taiwan to the U.S. in the late 1950s. His father, Jaming, completed a master’s in physics, eventually completing a Ph.D. in electrical engineering as well; his mother, Clara, has a master’s in accounting. They met in Chicago, then made their home in Homewood-Flossmoor, a suburban area south of the city. Dr. Pan senior taught at Purdue University-Calumet, in Hammond, Ind., just over the state border; it was less than a half-hour commute, which gave the family the best of both worlds: steady employment, while continuing to live close to the city they loved.
When Wilbur was a boy, his father built a set of bookcases for their home, a project that Wilbur found inspiring. You could turn some bit of creative imagination into practical, handsome objects for the family? Pretty amazing, when you think about it.
Wilbur attended Northwestern University, then graduated with an M.D./Ph.D. from the University of Illinois College of Medicine in 1994. After completing his pediatrics residency in Dallas, he did a fellowship in pediatric hematology/oncology at Children’s Memorial Hospital/Northwestern University Medical School back in Chicago. Bart Kamen, an attending physician he’d worked with in Dallas, happened to get in touch one day; he asked whether Wilbur might be interested in caring for children with brain tumors…in New Jersey. On a lark, says Wilbur, he flew to New Jersey for the interview; on the way back, he had a job offer – the hospital wanted him to build a pediatric brain tumor program from scratch.
By this time, Wilbur and Mary, a Chicago native, had married. They moved to New Jersey with a mutual understanding that they could always move back to Chicago if the East Coast didn’t feel like home. That was 21 years ago; they’re still in New Jersey.
His shop is in the basement of their house, which was built in the 1940s. On moving in, they learned that their neighbor Marc was an excellent woodworker who had built the kitchen in his family’s house, as well as most of their furniture. Wilbur credits Marc with showing him the difference between a finely sharpened tool (specifically, it was a handplane) and one that…well…is not.
Having lived next door for many years, Marc was able to share what he knew about the Pans’ new-to-them house. The father in the previous family had used part of the basement as a woodshop – one wall still had the painted outlines of tools he’d hung there. Marc recalled that after spate of noisy banging around, his former neighbor emerged from the basement with a boat.
In around 2006, Mary thought a gift certificate to a woodworking class would make a good present for her husband. Marc referred her to an adult education program run by their county’s community college. The teacher, Mike Zaslav, had trained at the College of the Redwoods. Wilbur signed up.
“I go to the first class and Mike spends the whole time teaching us how to sharpen a chisel,” Wilbur reports. Wilbur was hooked. He learned how to sharpen and picked up the basics of working with power tools. He made his first dovetail joint, edge-glued boards together and made his first mortise and tenon.
Beyond that course, his training as a woodworker has been less formal. “It was a lot of me messing around and reading, and trying to figure out how things work.”
When Wilbur was first getting started in his 10’ x 20’ basement shop, he understood that he’d be working with limited space. He had to choose between a table saw and a band saw – the shop was too small to accommodate both. He chose the bandsaw. Besides its small size, his shop’s location beneath the family living space led him to minimize the production of fine-particle dust, which the HVAC system would spread around the house; both of their kids were young, and Wilbut knew the kind of damage dust can do to children’s lungs. Hand tools would be better for everyone.
Then Wilbur learned about Japanese hand tools. So many woodworkers were crazy about them and considered them superior to Western tools. He couldn’t figure out why they had the cutting properties they did, so he starting researching the question through practice, as well as reading. He was intrigued, as a woodworker, as a scientist and as an American of Chinese descent. “Probably the whole Asian thing kicked in and it was easy for me to get interested in them,” he suggests (I imagine with a wink).
His father had taught him to look at things from the perspectives of science and reasoning, so Wilbur was not about to accept that Japanese tools were superior without some systematic investigation through reading, reasoning and hands-on research. “Japanese woodworkers have the same priorities as Western woodworkers,” Wilbur says. “They have sharp pieces of metal that they use to shape wood so they can build things, and they want to do things as efficiently as possible. If that was true, then the tools must be similar,” he inferred, adding “at least, in certain ways.”
He decided to focus on how the tools were similar instead of how they were different. Based on his research to date, he says, “If there is a divide, it’s not an East-West thing but a pre-industrial versus industrial thing,” He shared what he learned along the way through his blog, articles, an “End Grain” essay for Popular WoodworkingMagazine and presentations at Woodworking in America. It was at Woodworking in America that Wilbur first came to my attention.
“It’s true that there are obvious differences between Japanese and modern Western hand tools,” Wilbur acknowledges. “But if one looks at pre-industrial Western hand tools, when blacksmiths were making chisels and plane blades, there are similarities that stand out. Chisels and plane blades were made by forge-welding a hard piece of steel to a softer piece of steel. And both chisels and plane blades were made in a way so that there was some concavity to the back, for ease of sharpening.
“My approach is that I want to present a straightforward explanation of how to use Japanese tools. I try to stay away from the Zen stuff. I go on the assumption that the audience’s workshop is your typical hobbyist workshop in the U.S.; I’m not expecting people to work on the floor. The things I teach are centered on your typical woodworking shop – I have a typical workbench, a band saw and a drill press.”
What about Chinese tools, I wonder? After all, they would be more directly related to Wilbur’s cultural heritage. “For woodworkers, China has a tradition that may be more interesting to woodworkers interested in furniture making,” he replies. “There’s tansu [in traditional Japanese woodworking], but people in Japan didn’t have chairs and tables for the most part. They sat on the floor.
“China had furniture you’d recognize, made with tropical hardwood species – lots of rosewood and ebony. The joinery is very intricate; decoration can be very elaborate. But not much is known about the tools that Chinese woodworkers used.”
He attributes the differences between what’s known about Japanese and Chinese tools partially to differences between the two cultures in how they think about objects. “I think there’s a case to be made that in Japan, objects seem to be fetishized. There seems to be this reverence for objects that doesn’t exist to the same extent in China.”
For example, in Japan, much attention has long been paid to samurai swords. China has a similar tradition with respect to swords, but in China, swords occupy a less-central position when it comes to symbolic appeal. “In a Chinese movie a warrior may have his sword that’s a family heirloom. And then he loses or breaks his sword in a battle,” Wilbur has noticed. “He picks up something else, like a chair, and fights with that.” In Japanese films, the warrior often seems lost without his sword.
In China, he says, tools were historically valued in instrumental terms: They got the job done. The Cultural Revolution resulted in the loss of much traditional knowledge; such information is still hard to come by, especially for those who are not based in China. “It’s coming back, though,” he says, mentioning a school that teaches traditional techniques for carving with hand tools. But today, he notes, this school also teaches students how to carve by CNC, because they recognize it’s a means to produce furniture that’s affordable to vastly more people.
Wilbur values woodworking as a counterpoint to his daily work. He still cares for patients, although now indirectly as a director of breast cancer clinical trials for the pharmaceutical company Merck; he left pediatric oncology after 18 years on faculty at the Rutgers Cancer Institute of New Jersey and Rutgers Robert Wood Johnson Medical School. But when it comes to his medical work beyond basic physical exams, it’s very hands-off. He spends “a lot of time in front of a computer.” As a result, he says, “woodworking fills this urge to be able to create something physical and scratches an itch I think a lot of people have.”
That said, he notes that while “a lot of things in medicine are done with protocols and algorithms, there is a lot of creativity in medicine because there’s always the patient that comes along and doesn’t fit any protocol. So you have to figure out how to take care of that patient. Plus, the process of diagnosis is a creative act, because there’s a puzzle you’re solving.”
He ends with a nice metaphor. Several years ago he made a joined box (pictured above), “a completely American form going back to the late 1700s in the Philadelphia area.” The one he made “looks just like an old one.” But he made it entirely with Japanese tools.
“It doesn’t matter what part of the world your tradition comes from,” he concludes. “There are more similarities than differences than you might think.”
The following is from “Ingenious Mechanicks,” by Christopher Schwarz – this excerpt from Chapter IV, by Suzanne Ellison.
Tracing the history of workbenches takes one into the realm of Greek myth, along ancient trade routes, through the harshness of secular and religious empire-building and the glories of golden ages in arts, science and literature. There are many frustrations in the great gaps in the records, and regret over the loss of civilizations, languages and traditions. But the one thing that never disappoints, and alleviates the frustration and regret, is the wonder of human ingenuity.
The research for this topic began in 2014 when Christopher Schwarz asked me to translate an 18th-century description of the fresco from Herculaneum. I picked up the Herculaneum trail again in 2016 to search for contemporary accounts of the excavations and also 19th-century accounts of the condition of the fresco. Here and there, in other research, a low Roman workbench would turn up, but the majority of the images Chris uses in this book, and the workbenches discussed in this chapter, were found in June through September of 2017.
I primarily used publicly available image and text databases maintained by museums, universities, photographic archives, auction houses, academic journals and papers, and used search terms in seven languages. Occasionally, I contacted an archivist or academic researcher, and (with few exceptions) they were more than willing to offer assistance. A conservative estimate of the number of images viewed last summer is 8,000 to 10,000, with images from the Spanish Colonial era contributing about a third of the total.
Verifying the geographic origins of the artwork was the starting point to connecting commonalities in history and development of workbenches with distinctive features.
In the last couple years more public and private museums and universities have collaborated to put collections and other resources online. As we get more access there will be many more discoveries to be made, and I expect the gaps in our timeline will be filled. You may find, as Chris did, a missing piece in the puzzle is in a museum near you.
The Earliest Discoveries: 1st-15th Centuries As Chris and I unearthed examples of the low Roman-style workbenches, there was an emphasis on dating the benches and thinking in terms of a timeline, especially a timeline of innovations. Thanks to my father’s brilliant idea of handing me a map to track our family trips, and to keep me quiet on those trips, I started thinking in terms of maps. I had a workbench-discovery map developing in my head. Date, and place, would become important in solving some of the questions about the technology and the quirky features we found.
Low and higher workbenches and shaving horses are seen in flat outline in Roman funerary iconography, but for our purposes we start with four benches depicted in more dimension and detail. The first four low benches date up to the Roman Empire in the second century. Three are from the heart of the Empire: an engraving of a fresco from Herculaneum; a fresco depicting the myth of Daedalus and Queen Pasiphae from Pompeii; and a piece of decorated Roman glass found in catacombs. The fourth find, and the only extant benches, are the two from Saalburg, the frontier fort on the Limes Germanicus in the Roman province of Raetia. The Saalburg benches had the added interest of puzzling notches, a mystery that was solved, we think, by a Spanish painting executed more than 1,500 years later.
After a gap of six centuries in our record I found an 8th-century fresco of a carpenter working while sitting astride a low bench. The fresco was in an Umayyad bath house in the desert at Qusayr Amra (present-day Jordan), in a region once part of the Roman Empire. The bath house follows a Roman plan and the fresco is one of several “portraits” of the craftsmen who built the structure. After another six-century gap, five benches show up in 14th-century Spain and Italy. The Spanish bench is from Teruel Cathedral in the Aragon province of Zaragoza. Two decades before Qusayr Amra was built, the Umayyad led the Muslim invasion of Spain. In Teruel, Mudejar craftsmen (Muslims who remained in Spain after the Reconquista) built the cathedral and are depicted in portraits similar to those in Qusayr Amra. The Mudejar woodworkers were using low Roman workbenches. Of the Italian benches, one is from a Sephardic manuscript and three are scenes from the construction of Noah’s ark.
In the 15th century, low benches are depicted in Flemish and French paintings of the Holy Family, and in two books from southwest Germany and central Italy. Karl Schreyner, a woodworker in Nürnberg from about 1425, is one of the woodworkers in “The Mendel and Landauer Hausbücher.” In 1485, a woodworker and his bench are on the cover of a novella published in Florence. Both are notable because they are not religious images.
Each time there is a large gap in the image record, huge societal shifts were at work. In the 2nd and 3rd centuries, the Roman Empire was weakened by plague outbreaks that caused troop shortages and disrupted food production. During the 3rd century, there was a 50-year-long crisis that saw the Empire split into three warring parts. The devastation of wars and plague led to population shifts and, despite a reunification late in the century, there were cities in the western part of Europe that never recovered. In the 3rd and 4th centuries, the Empire struggled to keep control over its vast territories. And by the conclusion of the 5th century, the Roman Empire in Western Europe and the age of Classical Antiquity was at an end.
With the advent of the Early Middle Ages, Western Europe splintered into small kingdoms and city states. In the East, the surviving portion of the Roman Empire attempted to retake Italy and other areas lost to invading tribes. It was, to say the least, a time of great social and economic upheaval, and not every invading or land-grabbing group put record-keeping at the forefront. Artwork from the time does include scenes of woodworking, usually of a Biblical theme, rendered in manuscripts, frescoes, tapestries and mosaics. Representations of the construction of Noah’s ark have yielded a few low workbenches. To Chris’s delight, a series of benches in an early 14th-century Northern Italian manuscript have full face vises.
Two things to consider concerning the lack of image records from the last centuries of the Roman Empire and through the Middle Ages are: Who commissioned the art and who controlled what could be made? In other words: Who had the money and who had the power? The answer: wealthy landowners and the Catholic Church. For the wealthy, a nice selection of art might include portraits to exhibit the richness of your garments and jewels, illuminations for your Book of Hours and tapestries illustrating scenes from the Bible (and to keep out the cold). The Church commissioned frescoes to teach illiterate parishioners lessons from the Bible and the life of Christ. The civic authorities of a city state might commission artwork illustrating themes of good government and portraits of city luminaries. Artwork featuring woodworkers and other craftsmen, all of the low end of the social and economic scales, was not desirable.
How the artwork was made also figures into what survived. Manuscripts and paintings were easy to move to safety, or be looted then saved. Frescoes can be incredibly durable, but given the great age of any work created in this time period they are, nevertheless, fragile. Add in questionable conservation methods and the countless wars and conflicts extending well into the 20th century, and it is remarkable we have anything left to ponder and appreciate.
Many operations on low workbenches seem difficult or a lower-back nightmare until you overcome two obstacles. The first is that many operations are much easier when you are sitting down. Not just sitting on the bench but sitting on a sawbench or stool that is next to the low workbench. Dovetailing while sitting isn’t difficult as long as you allow your sawing arm to swing freely – just like when you are standing while dovetailing.
Likewise, traversing a board with the side stops (detailed below) is fairly easy. The worker remains stationary in front of the side stops and the board is moved from right to left. So, before you dismiss an operation as impossible with a low workbench, sit on it for a while before you pass final judgment.
The other obstacle to consider is your smooth, modern floor. Many low benches will move quite a bit because they lack the mass of many taller workbenches. Many early shops had dirt floors, or the work was performed outside (the book “Woodworking in Estonia” made this clear to me).
So, take your bench into the yard or find a way to immobilize the legs, especially for traversing. A quick solution is to purchase some adhesive anti-skid pads at the hardware store. Those help for all but the heaviest work.
Although a back may not call for the high finish that is necessary for, say, a cabinet door, it needs to be strongly made and of a type to suit the particular job. “Craftsman” discusses here some of the points to be considered when deciding just what kind of back a job is to have. —Ed.
I AM afraid that many of us are inclined to let the backs of our cabinets take pot luck, as the saying goes. We make a job, say, in oak, possibly putting in oak drawer sides, and backs, but hesitate before going to the expense of oak for the back. The reason (or excuse, however you happen to look at it) is that it is seldom seen, has little or no wear to withstand, and that, since the cheap back answers the purpose just as well, it is clearly a waste to spend money on an expensive one.
Well, it is logical enough up to a point, and, providing that it is merely the material that is cheapened and not the method that is worsened, no great harm is done. In fact, there are many pieces of quite light woodwork in which a heavily built back seems almost out of place. Still, it is nice to have a piece of work in which nothing has been skimped, and the argument that a cheap back answers the purpose as well as a better one may not necessarily hold good, as we shall see later. The safe plan is to consider each piece on its merits, and give it the best back that it is worth.
BACKS OF OLD FURNITURE If one goes back into the past one comes across some curious anomalies. Many of the antiques of the Queen Anne and mahogany periods of which we think so highly had wretched backs. I myself spent a good many years in a repair shop, and I can speak feelingly of the hours I devoted to gluing strips of canvas across gaping splits in panels and across open knot holes. I have seen a mahogany chest of drawers of the Chippendale period with magnificent show work—serpentine shaped drawers, fine carving, and so on—with a back consisting of pieces of 1/4 in. pine nailed across. An extraordinary inconsistency. Apart from its having no strength, the whole thing was bound to shrink and split.
Yet when we come to that much abused period of Victoria, we find exactly the reverse. Probably no finer cabinet backs have ever been fitted into furniture. Open the door of one of those huge Victorian wardrobes (there are plenty of them knocking about in seaside boarding houses). You will find the mirror back more strongly made than many a modern wardrobe door, and the carcase back a finely panelled framework often with moulded stiles or flush panels.
Perhaps one reason why there has been a tendency to fit lighter backs since Victorian times (apart from the all-round cheapening of materials and construction) is the introduction of plywood. It seems such an obvious use for ply, a material which is free from shrinkage and obtainable in such large sizes. Undoubtedly it is perfectly suitable for the purpose, providing the carcase is strong in itself, and does not rely upon the back to make it rigid.
TYPES OF BACKS There are various considerations that affect the choice of a cabinet back. There is, for instance, the question of size. A single sheet of 3/16 in. plywood might make an excellent back for a little cupboard, say, 15 ins. high, but would obviously be absurd for a wardrobe. Apart from this, however, the first consideration should be: does the job rely upon the back for strength, or will the back serve merely to enclose a space? Fig. 1 shows the idea. At A the back is needed to prevent racketing and to stiffen the carcase generally. At B, however, the carcase is already strong, and only a light back is needed.
In the latter connection, of course, it is sometimes an advantage to build in the back with the carcase. Items such as sideboards are often made in this way. As a general rule, however, it is better to make the back separately, because it simplifies the subsequent fitting-up.
THE PANELLED BACK For a thoroughly strong back the panelled type is undoubtedly the most satisfactory. It is perfectly rigid and is free from all shrinkage complications. It should always be used for pieces such as cupboards with large, heavy doors, which are particularly liable to distortion unless provided with a stiff back. Fig 2 shows the usual form. The whole thing is put together with mortise and tenon joints, and the panels are grooved in. One point to note is that if there is a shelf in the cupboard, the middle cross rail should be arranged opposite to it if possible. It may not always be practicable, of course, but the advantage is that it gives a level surface against which the back of the shelf can face (see B, Fig 3). If this is not done there will be gaps opposite the panels as shown at A.
The same difficulty sometimes occurs in a bookcase or similar item, but owing
to the large number of shelves it is not practicable to arrange for many horizontal rails. The better plan is that in Fig 4, in which the panels are flush with the framework at the inside. It necessitates fairly thick panels, of course, but it gives a far neater result than cutting out the back edge of the shelf to fit.
MUNTIN BACKS A somewhat distant relative of the panelled back is the muntin type. It is nowhere near as strong, and is rather a doubtful member of the family. Like some relations, you can’t deny them (and they are useful sometimes), but you are a little shy about mentioning them in the best circles. It consists of a series of uprights, say 3/4 in. or 7/8 in. thick grooved at the edges to take thinner panels, as shown in Fig. 5. The ends of the muntins are cut away as shown inset, so that the panels can be fixed directly to the back of the carcase.
Now, as the panels are generally about 9—10 ins. wide, and of deal, it is inevitable that a certain amount of shrinkage will take place. Consequently it is a mistake to drive in nails right across the width because the wood would split in the event of shrinkage. The better plan is that in Fig. 6 in which nails are driven in near the centre only. The edges extending into the muntin grooves are free so that they can draw out. Note that the heart side is outwards so that the free ends are pressed tightly against the carcase by the natural twisting tendency of the wood.
If, owing to the presence of a number of shelves, it is desirable for the back to be entirely flush on the inside, the muntins can be rebated instead of grooved as shown in Fig. 7. The beads along the rebates are not entirely decorative, but they serve to render the gaps less noticeable in the event of the panels shrinking. All these details about shrinkage apply only when solid wood is used, of course. In the case of plywood it does not matter.
Speaking of plywood brings us to another variation of the muntin back. In its simplest form the plywood back is nothing more than a sheet of plywood nailed or screwed in a rebate. For quite light jobs this is satisfactory enough, but to give a neat finish the back in Fig. 8 is better. A series of grooved and rounded horizontals is screwed on. They can be arranged level with the shelves as shown. The plywood panels fit between them in the grooves. For a flush effect the rails can be rebated instead of being grooved (see D).
DRESSER BACKS These are really in a class by themselves, for although they could be applied to pieces such as wardrobes, they are not so strong as a panelled back. One of two methods can be followed. That shown in Fig. 9 has the advantage of simplicity. The back is really a series of matched boards, tongued one into the other, with either a bead or a V worked at the joints. The boards are screwed or nailed directly to the top and shelves, and at the bottom to a rail specially fitted for the purpose. In the second method, Fig. 10, wide grooved rails are screwed at top and bottom and the matching fitted in the grooves. The wide rails give rigidity, the matching merely filling the space, so to speak. It can be either very thin as at A, or it can be stouter, the ends being tongued as at B.
Incidentally, a detail applying to all backs of any thickness is that the rebates in the ends should slope as shown at A, Fig. 11. If this is not done the projecting portion is liable to curl as shown at B.