Prior to electricity, equipment was powered by animals, water or even humans. Today, many power tools, or at least the shop versions of them, can be converted to work even without electricity.
The machine shop existed long before electric motors powered the machines. Animals turning a large horizontal wheel would send power through an axle into the shop. The machinists would then use leather belts to transfer that power to their lathes and milling machines. This allowed them to cut metal much like a modern machine shop does today.
One of the easiest pieces of power equipment to convert back to older means of motive power is the sewing machine. This could come in handy during a long-term blackout – or even today if you just are curious how your ancestors once lived.
If we take off the molded plastic covers and look at what’s inside, we’ll find that the sewing machine hasn’t changed much through the years. While modern sewing machines may have built-in embroidery stitches, those are more of an add-on than the basic machine.
Before electric motors, sewing machines were powered by treadles. The seamstress or tailor would sit at the machine, powering it with their feet, while their hands guided the fabric. When electric motors were invented, the exact same machines were retrofitted, replacing the treadle and flywheel with a motor.
In this cutaway view of a modern sewing machine, we see the major power components. The motor (1) provides the electrical power, which is transmitted to the upper pulley (2) by a belt, which is shown in black. The upper pulley transfers power to the sewing machine head through the upper axle (3) and to the bobbin through the lower axle (4).
If we were to remove the motor from the sewing machine and replace it with some other power source, the machine would still work because the only part that really needs the electric power is the motor. Everything else works from mechanical power that the motor provides.
So, to make this machine work by treadle operation, all we really need to do is to remove the motor and add the treadle, with a new belt to replace the existing one, which would be too short.
How the Treadle Works
A treadle sewing machine is really only two parts, connected by a rod. The treadle itself is mounted in bearings, allowing it to be rocked back and forth by the feet. This provides the motive power, in more or less an up and down motion. That has to be converted to a circular motion, which is done by connecting it to a flywheel.
We’re going to look at a modern treadle machine, as it is easier to see the various parts. Old-fashioned treadle sewing machines had ornate cast-iron stands, which would make it difficult for us to see the individual components, especially the flywheel. Nevertheless, they operated exactly the same.
In the photo we see the treadle (1) is mounted to the frame of the sewing table or sewing machine stand with two bearings (2). These need to be mounted exactly across from one another, to ensure that the treadle mechanism will operate smoothly. Ideally, these should be greased bearings or they will end up wearing out from prolonged use.
A flywheel is mounted into the cabinet between the treadle and the machine. In this case, the flywheel is providing two different, but interrelated functions for us. The first is to convert the linear motion of the treadle to a circular motion. This is done through the connecting rod (4) being attached to an offset arm on the flywheel (see diagram below). The second function is the traditional function of a flywheel to store mechanical energy as momentum, ensuring smooth operation of the sewing machine.
The only thing left to make our sewing machine work is a belt to connect the flywheel to the sewing machine pulley. As you can see in the photo of the treadle-operated machine above, this is normally done by putting the pulley inboard of the hand wheel, in plain sight. However, with the machine in the cutaway view, this would be difficult to accomplish with the case in place. Therefore, we’d need to cut a slot in the bottom of the machine’s case for the belt to fit through.
Putting it Together
The easiest way to build this project is with an existing treadle mechanism. These are available from antique stores and secondhand stores. I’ve gotten a bunch from Goodwill at one time or another. The advantage of starting out with an existing treadle mechanism is that all you need to do is build the tabletop and attach the machine.
However, if you don’t have one available, it is still possible to build a good treadle mechanism yourself. The design is simple and straightforward enough that anyone with fairly good handyman skills should be able to build one.
There are two keys to building this mechanism. First of all, we need to be concerned about the smooth operation of the treadle mechanism. In order for it to operate smoothly, it will need to be of rigid construction, with ball bearings for the pivot points. I would recommend against sleeved bearings, as they will wear out too soon. Properly aligned, with the bearings lubed, the treadle should operate effortlessly. If you have to work at it, there’s something wrong with the bearings or the alignment.
You can make a treadle out of metal or wood. I’ve done both, for machines that I’ve converted. Most of them have been wood, simply because it is easier to work with. But a metal treadle is less likely to have problems with falling apart from extensive use.
The flywheel needs to be bearing-mounted as well. With the belt and connecting rod unattached, it should be able to continue spinning for quite a while, once you spin it. For this to happen, the flywheel itself needs to be properly balanced. If it is not, it will become obvious when it is slowing down.
The basic idea of any flywheel is to have a large mass that is as far from the axle as possible. The farther the mass is, the more energy it can store in the form of rotational momentum. That’s why the flywheel is open, with a thick solid edge. You’ll be best off if you can find a flywheel somewhere that you can use. But if you can’t, a brake disk off of a large truck or bus will work well. Although it will be heavier than necessary, that isn’t a problem. The edge of the brake disk, where the web is between the two plates, makes a good track for the belt.
You can lighten up the brake disk by drilling or cutting a series of holes in it, just as long as you keep them at least 3/4″ from the edge.
Mount the treadle and flywheel together in a cabinet and connect them with the connecting rod. You may need to fiddle with the rod length a bit, as it will affect the angle of the treadle platform. If you use all-thread for the connecting rod, it will be easy to adjust to any length.
While the belt is traditionally made of leather, it can be made of pretty much any material. I’ve used string before, using several loops to help keep it tight. A very easy and effective way of making a belt is to use 3/16″ nylon rope, like you would use for a clothes line. Cut it to length, heat the ends and melt them together. Once cooled, the extra material can be ground off. This provides a belt that does not have any knot or other obstruction to keep it from running smoothly.
What would you change, if anything? Share your thoughts in the section below: