Tools of the Trade

Tentmaking Made a Little Easier

This is an article I've wanted to write for a long time, because many people start making tents but get discouraged when they get the job underway and find themselves struggling. Over the years, I've learned a few tricks about how to make the project to go easier. Much of the trouble goes away when you have tools that work for you instead of against you, and that's what this article is all about.

Part 1: Sewing Machines and tables

The basic sewing tool nowadays is the sewing machine, which is the main reason that period tents are available at reasonable prices. Otherwise, the cost of labor would make them prohibitive to all but a very few. One of the first questions I get in my tentmaking classes is "What sort of sewing machine should I use?"

The answer is that any sewing machine will work, as long as it's rugged enough. Industrial machines are the obvious first choice, especially if it's fitted with some sort of mechanism for feeding the material through the needle area. These machines are designed to run twenty-four/seven if they need to, with a minimum of maintenance. Although they are pricy, they can be rented by the day or week around most metropolitan areas; call the various sewing machine suppliers in your area to see if they have that service.

The key to whether a home machine can do the job is mostly a question of gears ... specifically, whether they're made of metal or plastic. Most of the older machines (prior to around 1970, I'd say) used metal gears and could be subjected to a lot more abuse without breaking. Steve Peck likes to tell about how he tore up the plastic gears on his machine, but found when he took it in for repair that these gears could be replaced with metal ones. He had this done, and this machine is the one he uses for all his heavy sewing nowadays.

Another factor is how powerful the motor is, and how efficiently the feed dog works in moving the material through the machine. This doesn't affect the quality of the stitches very much if you sew very carefully, but it affects the speed at which you are able to sew a seam. The weaker machines require a lot more attention in regulating the pace of the sewing and feeding the material through the seam.

Feeding mechanisms

Sewing machine motors, no matter how powerful, can use all the help they can get, and canvas workers have devised a variety of mechanisms to help get the fabric through the machine. The three most prominent feeding mechanisms are the walking foot, the puller, and the gravity ramp.

The walking foot pinches the cloth against the feed dog and moves with it, instead of just applying pressure against the feed dog and counting on the dog's traction to move the fabric along. Most of the industrial machines made specifically to handle canvas and leather use such a mechanism. My main machine is a Pfaff 545 with a walking foot, although I've used well-made walking-foot machines from Japanese manufacturers like Juki, Consew, and Brother.

A lot of these Japanese manufacturers designed their machines to use parts in common, which increases the odds that your repair person will have the proper replacement part in stock at a reasonable price. (But when it comes to parts for industrial machines, your idea of a reasonable price may not agree with the manufacturer's.)

The puller is a gadget seen most often on sailmaking machines, notably those made by Bernina (although I've seen a few Berninas and other models retro-fitted with them by California sewing-machine suppliers). In the conventional setup, the foot is first engaged, as in a regular sewing machine. Then, if desired, the puller's roller is lowered onto the work and becomes the primary mechanism for feeding the cloth. The roller is driven by the same gear system that drives the feed dog, and is adjusted so that it feeds the cloth through just a tad faster than the feed dog. Sailmakers prefer this system because it allows them to use a wider foot that accomodate the large zig-zag stitches that they use on sails. ("Why zig-zag?" I hear you ask. Because that seam with stretch with the fabric, eliminating the aerodynamically undesirable tension or "pucker" line that would otherwise result from the sailcloth stretching faster than the seam line.)

I have two puller-equipped Bernina 217s, one with a puller setup from the factory which is very slick. They were bought primarily for the sail work I do, although they are often used for straight-seaming work. The big trouble with Berninas is that the parts are expensive. As a sewing machine dealer told me, "The Bernina is the Porsche of sewing machines, and you've got to expect to pay Porsche prices."

The third system, also used by sailmakers, is the gravity ramp. As the name suggests, it's simply an inclined ramp that feeds the cloth through the ramp. It's by far the cheapest system, and sailmakers claim that it's the easiest to regulate, since gravity doesn't change much from day to day. It looks like this:

I remember the slope as being roughly 7 or 8 degrees in one of the lofts I worked in, but it isn't critical. The ramp is to be about the length of the longest seam you commonly sew, usually six or seven feet (although longer seams can be sewn if you fold the work accordian-style and have a helper around to refold the work as it hits the bottom of the lower ramp). The most awkward part of using a gravity ramp is muscling the cloth back up the ramp when you have to back-stitch, but sailmakers don't usually do much of that.

The gravity-feed system can easily be improvised from whatever four-by-eight paneling you may have available ... plywood, particle board, masonite, or paneling. Since it doesn't have to be pretty or even full-width, it's worth trying your local purveyors of such stuff to see if they have any damaged, cracked, scratched, scuffed, or otherwise discountable panels in their stock that they'd be willing to part with at their cost or a little over. All you need to make it serviceable is a little paste wax to let the fabric slide down the ramp a little easier. At the loft, we finished it with a urethane varnish, waxed it with floor wax, and kept it touched up with a silicone spray to keep it slippery.

The sewing table

Here at the shop, my sewing table is twenty-four feet long and twelve feet wide, with the sewing machine installed halfway along one side. This gives me twelve feet in front of the machine, twelve in back, and twelve on the side ... enough to spread out large sections of material. You probably don't need anything quite that big, but you should have enough to be able to support the length of a panel seam front and back. If your side-walls are six or seven feet high, two piece of 4' x 8' paneling, plywood, or whatever will make a decent front-and-back table when supported by sawhorses so that the paneling is the height of your sewing table. The advantage of this system is that you can easily configure it into an 8' x 8' cutting table, move it around indoors or outdoors, and break the whole thing down for easy storage when it isn't in use.

Sky hooks

Well, they're not really used to hang things from the sky, but I like the term. What we have here at the shop is a variation of what I saw parachute makers do at the Pioneer Parachute Company, where I did some production engineering in the early 1980's. Their seamstresses had to sew the skirts of, and attach lines to, the huge parachutes used by the military to drop heavy equipment. They solved the problem of handling the massive amounts of material by hanging the parachute from the ceiling by its apex, with the skirt right at the level of the sewing machine. The suspension system carried the whole weight of the cloth, so the operators only needed to maneuver the adjacent part of the parachute through the machine. If your sewing area has a high ceiling (about twelve feet or so), you may be able to use this system when sewing the bottom of the canopy of the tent, as shown in the figure below.

A "sky hook" setup being used to help sew a valance to a canopy

A pulley is attached to the ceiling, and a rope is fed through it. One end of the rope has a C-clamp and a carabiner on it, and the material to be sewn is attached to the pulley either by a loop fed through the apex hole and clipped to the carabiner (if the workpiece has an apex hole) or by being clamped with the C-clamp (if it doesn't). If the material is clamped, the clap should be well padded so that the workpiece's fabric isn't crushed. The workpiece is then raised to the appropriate level, and other end of the rope is attached to a cleat to the workpiece at the right height.

Needles and thread

The right needle, as Goldilocks might say, is one that's not too big and not too small. The people who sell you the thread should be able to make the best recommendation, or direct you to the manufacturers of the thread or the needles. Or you could try with an assortment, starting on scrap with the larger ones and going down a size at a time until you start having problems.

Your present sewing machine needles are probably too small to sew canvas, and that's not good. Sewing canvas creates a lot of friction, friction creates heat, and smaller needles don't do as good a job of dissipating heat as the larger ones do. Therefore, they overheat and lose their temper, which makes them flex weirdly, miss stitches, and maybe even shatter or plunge into the hook or worse, making you lose your temper. Also, smaller needles have smaller eyes, and running a heavy thread through a small eye can throw off thread tensions and affect the ability of the top thread to form a loop big enough for the hook to catch as it rotates.

The temptation is often to be on the safe side and use a larger needle than you need. That's better than going too small, but it's not an ideal solution. Since you are poking a hole into the material with every stitch, and bigger holes make it easier for moisture to seep through the tent roof, it stands to reason that you don't want to make holes too big.

There are two schools of opinion about the proper needle point. Some manufacturers use only "ball end" needles, on the theory that the needle will be less likely to cut the fibres of the material. Others (myself included) feel that this theory works better for sewing done at a relatively slower rate, but that for a machine running fast or powerfully, a sharp needle will be less likely to damage the material, since it is better able to push the fibers aside rather than crush them with blunt force. It really doesn't matter much. Use the ones that give you the best result, or can obtain the cheapest.

How often do you change a needle? I change it when it starts screwing up. As experienced sewers know, it will eventually get to the point where you can sense it by a slight increase in noise or effort from the sewing machine. When I was running a six-machine sail loft, I could often hear a dull needle from across the room! But there are other indications, too. If you use an industrial machine that uses needles without a flat side, you can check the straightness by rolling it along the table and seeing if the point "wobbles." Or examine the point of the needle with a magnifying glass. If you can see a glint of light anywhere on the point, the point has a flat spot and has to be replaced. But lots of times, you just can't tell when a needle is due to be replaced. My advice: replace it, and see if the fresh needle makes your sewing easier. If it doesn't, there probably was still some life left in the old one.

As for thread, the people who sold you the fabric will probably have some recommendations. I prefer a polyester "anti-wick" thread since I haven't seen a cotton thread that will match it for strength and durability. Cotton threads are weaker and more prone to weather damage, but have the advantage of swelling slightly when wet and sealing the seam. You generally want to match the thread to the fabric, material-wise, although I've had good luck sewing all-cotton material with all-polyester thread. I wouldn't recommend sewing synthetic materials with cotton thread, though, since it's a drag to have the seaming thread wear out before the material itself does. Sewing seams once is a real trial, but who wants to do it twice?

Note: The Pavilion Book has additional information on sewing machines and recommended needle and thread sizes, as well as an extensive section on hand tools and how to use them.

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