This posting/article was inspired by two incidents in Downton Abbey. One in Season 1, where Carson comments on a footman's torn jacket-shoulder and one of the housemaids sews it up, and another in Season 2, where Miss O'Brien compliments Mr. Mosley on his sewing-skills in the kitchen, adding that "people nowadays think that they can be a valet just because they can tie a shoelace!"[I]
In a house like Downton, with a large family, an extensive staff and a small village and farms nearby, the presence in the community of a tailor, seamstress or dressmaker would've been important. But such small communities are unlikely to have one. To that end, even in the Edwardian era, and all the way up to the 1950s, it was still fairly common for the lower and middle-classes to make their own clothes, or to repair clothes, and not just chuck them out like we do today.
To do this with any level of efficiency, they would require a sewing-machine. A grand house such as Downton would probably have just such a machine stored away somewhere for any real emergencies with regards to linen, tailoring, clothes, etc.
A Brief History of the Sewing MachineThe sewing machine was...um..."invented"...and I use that word cautiously, in England, in 1790 by English cabinetmaker, Thomas Saint. But it was barely a working machine. In fact, when a replica of it was built according to the original schematic drawings in the 1870s, the machine didn't work!
Improvements were made during the 1810s, 1830s and 1840s, but a really practical machine did not show up until the early 1850s.
It was at that time that the biggest name in sewing-machines arrived on the scene.
He was the son of a German immigrant and something of a mechanical whiz. His name was
Isaac Merritt Singer. His company, established in 1851, originally called
I.M. Singer & Co., would have been known by its most famous name, "The Singer Manufacturing Company", by the 1910s when Downton takes place.
Singer was undoubtedly the market-leader. Some brands are moderately famous...Pfaff...Husqvarna...White Rotary...Jones...
...but Singer was King. In a house like Downton, a strong and reliable sewing-machine would've been essential, for all the work it potentially had to go through.
But what kind of machine was it?
Types of Sewing MachinesBy the last quarter of the 1800s, sewing-machines finally stopped looking like crazy, mechanical science-experiments, and started looking more like the machines we know today. There are six basic types.
1. Treadle Machine
The treadle-machine was a completely mechanical device. Belt-driven and foot-powered, the sewer pedaled the foot-treadle up and down. This drove a crank which operated a big flywheel. This in turn pulled on the drive-belt which operated the handwheel at the top of the machine. This would drive the machine's mechanisms, which were all hooked by levers and pistons to the handwheel assembly.
Treadle machines were obviously, not very portable. They would've been kept, tucked away in the corner of say, the servants' hall, folded up and covered, looking like a side-table, until they needed to be used. Then, the lid would be lifted up and the machine pulled up, out of the recess under the table.
2. Handcrank Machine
Handcrank machines were just as common as treadle-machines, and they were considered the first portable sewing-machines. The operator cranked the machine (with a crank attached to the handwheel) with his/her right hand, while running the fabric through the machine with the other. The benefit of both hand and foot-treadled machines is that YOU, the USER, can fix EXACTLY how fast you want the machine to go.
The machine in the picture is a Singer 28k, with technology representative of that around the turn of the last century.
3. Electric MachinesAt the time of Downton, the first electric sewing-machines were JUST coming onto the market, but the vast, vast, VAST majority of the machines on offer were still mechanical, hand-cranked, foot-treadled models, well into the 1950s. The first electric Singer machines looked like this:

This is a Singer 99k knee-lever from 1950. But the 99k model was manufactured starting from 1920, in treadle, handcrank and electric knee-lever varieties (which is what you see there). The electric knee-lever machine changed very little between 1920s until the mid-1960s when this model was ended. This PARTICULAR machine in the photograph is my grandmother's personal machine. She was a dressmaker. She died last year at the age of 97 and I have inherited it. I'm currently undergoing an extensive restoration-project for it.
Then there's the three main types of machines...
1. Transverse ShuttleThe transverse shuttle machine was the first machine that didn't look like some sort of highschool shop-class experiment. It came out in the 1860s and looked like this:

It worked by having a boat-shaped 'shuttle' underneath the needleplate (the two steel plates that form a + under the machine-head) run back and forth, 'traversing' the needle, and making a stitch on each back-and-forth movement.
2. Vibrating ShuttleThe vibrating-shuttle mechanism sewing-machine was invented in the 1850s, but it was the 1870s and 80s before they became practical, working models. The first Singer vibrating-shuttle machines came out in the 1880s. This is the most likely contender for a sewing-machine in the Downton estate. They look like the Singer 28k which I showed up above:

The Vibrating Shuttle machines were made well into the 1930s. But by then, they'd become obsolete, replaced by the hook-machines.
3. Hook MachinesThe hook family of sewing-machines came out at the close of the 1800s. The rotary and oscilating hooks were used on the Singer 66, 99, 201, and most other Singer sewing-machines of the last decade of the 1800s up to the modern day. Nearly all modern sewing-machines operate on the oscilating-hook design created by Singer.
Uses of a Sewing MachineI know, you think I've lost my mind. I haven't...
These days not many people use sewing-machines for much more than repairs or decorations. But in Edwardian times, the sewing-machine, an important and EXPENSIVE household machine would've been used for ALL the sewing in the house.
Anything at all. Curtains, bed-linen, pillowcases, upholstery, clothing, repairs, belts, shoes, tablecloths...anything made of cloth in a house that you can imagine, was run through a sewing-machine.
Vintage sewing-machines were VERY easy to use and VERY easy to maintain. Designed for household use, they were expected to be completely self-contained, self-sufficient, self-reliant and self-fixing, almost. Built to be incredibly tough and long-lasting, antique Singers of over 100 years old, will still today, make you a full suit, or a complete dress, in the hands of a professional tailor.
If anyone reading this has a vintage or antique sewing-machine that's mechanically operated, that they'd like to get running again, post away and I'll be happy to help you get it running.
Historical NoteIn your RPG, I would be weary of using the word "seamstress"
In Victorian and Edwardian times, 'seamstress' was a euphemism for 'prostitute'.