My coworker said this buttonhole technique is an abomination, so I'm teaching everyone how to do it.
There's multiple kinds of buttonholes out there, but the two main categories are bound buttonholes and worked buttonholes. Worked buttonholes are made with thread, either on your sewing machine or by hand.
As someone whose job is to sell premium sewing machines, I can assure you that once you're spending $5000 on a sewing machine, you can do perfect, consistent, 1-step machine-worked buttonholes every single time*. But sewing machine that don't have a computer-feedback 1-step buttonhole often make the "consistent" component pretty difficult, which is annoying because on most projects with buttonholes, you have to make multiple, identical buttonholes.
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*Okay that's a lie, but you can get perfect machine-worked buttonholes 90% of the time, assuming you follow the instructions and use stabilizer. Probably.
If your sewing machine doesn't have an easy, consistent buttonhole setting, you can work them by hand. I recently did a blouse entirely with hand-worked buttonholes, because I sewed an entire blouse on a 1954's Singer Featherweight, just to prove to myself that I could do it. What I learned is that hand-worked buttonholes require knowing the right technique, and also require plain ol' practicing so that they don't look ugly as heck. If you don't have time, or don't have the desire to learn hand-worked buttonholes, there's more options for machined buttonholes, even on machines without zigzag stitching.
Look at how pretty this bound buttonhole is. In a worked buttonhole, the edges of the buttonhole are secured with thread. In a bound buttonhole, the edges of the buttonhole are secured with fabric. This picture is from an article in Threads that teaches you one of the proper ways to accomplish this.
Or you can do this thing that I do, which looks pretty much the same. I think my method is easier, or maybe it's just easier for me to understand. Anyway, my coworker said it's an abomination, so now it's time for everyone to learn how to do it.
To do this, you're going to need three fabrics. One of these is going to be your garment, or whatever you're putting the buttonhole in. One is going to be your facing, and one is going to be your buttonhole binding. Some people refer to the binding as "lips" and that feels weird to me.
A note on fabric selection: if you're doing this in a fabric that is not very thick and does not stretch, you can make your facing out of the same fabric as your garment. If your fabric has stretch (my white fabric is 2% spandex and so it does stretch a little bit), you want to use the closest fabric you can find that does not stretch. If your fabric is thicker, you want to use a thinner fabric that is as close to the color of your main garment as possible. If you for some reason can't match your facing to your garment, you can match your facing to your buttonhole binding. The point on the facing is that you want it to blend in on the off chance that it does show. For this example, my facing is the alien abduction fabric.
Your buttonhole binding is going to show. You can choose if you want to do a contrast binding, like I did in my tutorial, or a matching binding, like Threads did in that picture up there. Mistakes are easier to hide in a matching binding, but contrast buttonholes are more fun. You are the master of your own destiny in this case.
Place the buttonhole and the facing right sides together, on the spot where you want your buttonhole. Sew a line of stitching around the outside of your buttonhole. If you're doing multiple buttonholes, and they need to be consistent, you're going to need to figure out the best way to mark them so that they are all the same. I recommend making 2-3 buttonholes on scrap fabric just to make sure you can consistently do them all the same.
When you have your finished buttonhole, the binding will close up the space, so it's okay (and encouraged) to sew this original buttonhole box wider than you would normally sew it. You want to make your width of your box just a hair wider than the intended final size of your buttonhole, but you want the height to be much taller. If your buttonhole isn't tall enough, you won't have enough seam allowance to make a strong buttonhole. (The exception to this is doing buttonholes on fabrics that are stable when they're cut, like lycra or anti-pill fleece. I'll get to those later).
Using some sharp scissors, you're going to cut this shape into your box. If you want a square box with sharp corners (and you do), it's important to cut all the way into the corner. Don't cut the stitching, but come as close to it as you possibly can. Where these corner cuts are is going to control where your finished corners will be, so take some time and get them in a perfect square.
You can see here how I pulled my threads to the back and knotted them off. To do this, hold your bobbin threads very tightly, and use a seam ripper or a stiletto or a pin to pick up your top threads. You have to hold the bobbin threads, or else you'll just undo your stitching from the back. Once your top threads are all on the same side, you can tie them all in a knot and then trim the threads to 1/4". The tails will be hidden behind the facing when you're done, so you don't need to cut them super short. You'll also notice that I have some extra thread coming out of my lower left corner. That's because I messed things up while sewing this and broke a thread. You shouldn't have this thread coming out, unless you also messed up exactly like I did.
Push your facing through your buttonhole, and straighten it out on the other side. Press everything flat. This is a point in the process where it's really important to make everything look nice and square.
I don't have a picture for this, but when you're pressing your facing from the back, try to have a little tiny sliver of your garment fabric visible through the buttonhole. This makes sure that the facing isn't visible from the front. Also, while we're here, look closely at my picture on the right. You can see my printed facing through the fabric. This is one of the reasons why you want to match your facing to your front fabric.
Fun fact, if you want to, at this point you can just fold the facing to make the buttonhole binding. I don't like doing it this way, for several reasons, but the Reader's Digest Guide to Home Sewing says that it's a legitimate way to do these things. I don't like this because it's harder to get things lined up straight, looks worse when you're using a contrast binding, and is more likely to rip when you're actually functionally using the buttonhole. However, it's Technically More Correct than what I'm about to do.
It's time to get your fabric for your binding. As long as it's an appropriate weight, you can use pretty much anything. I have some printed gingham here. Get two pieces, slap them right sides together, baste them on your longest stitch length with a 1" (or more) seam allowance, and press the seam open from both sides.
Because I wanted my gingham pattern to be on the diagonal, I cut my pieces on the diagonal. If you want it straight, cut them straight. This is a great technique for patterns that you really want to match, because you're working with your pieces out in the open instead of trying to match them in a crunched up little space within your buttonhole. If you're doing something complex, like pattern matching a directional plaid on the bias, you can match up one single long seam, and then cut the bindings as you need, instead of having to match them over and over in little 1" sections.
Take your binding all pressed open, put it on your work space, and place your garment fabric over it, centering the box on the seam between the two pieces. You now want to secure the garment fabric onto the binding fabric, so that the two stay in place. My chosen method is to use some hand sewing needles as if they are headless pins (which of course I didn't take a picture of). This lets me flip the fabric around without my sewing machine foot running into pin heads.
Once your binding is secured, fold down your garment fabric. Do you see the little piece of garment fabric that's visible? Make sure you have that separated out, because you're about to sew on it.
Going as close to your fold as you possibly can without catching it (this is a good time for your zipper foot if you have one), you are going to sew your binding to your facing, and you are also going to sew that little trapezoid onto your binding and also your facing. I sew for an inch or so beyond the buttonhole, because it doesn't take any extra time and it does provide a little bit of extra security.
(Do not panic. I did fix my tension right after taking this picture).
You're then going to fold the garment fabric up so that you can access the same fabric trapezoid on the bottom of the buttonhole. Sew through the binding, the facing, and the little trapezoid.
Now, you're going to fold back the sides of the buttonholes, and sew the facing to the binding, making sure that you also sew through the little triangles at the sides.
Having to sew through these little bits of seam allowance is why it's important to make your box wide enough at the start of the process. With fabrics that can fray with pressure, you need at least enough fabric that the facing won't rip off the stitching. On a thinner fabric that's tightly woven, you will probably need at least 1/8" on the tops and the bottoms. On a thicker fabric that is more loosely woven, you'll need to go even wider.
So now it's time to take your whole mess on the back and trim it into something nice and neat. Pinking shears are good for this, because it decreases the chance of the patch burning through to the front. If you want to be extra precise and proper, you can trim your binding seam allowance to be shorter than your facing seam allowance, which will do extra work to make sure that your patch doesn't show up on the front.
Generally these patches are thick enough that they don't really risk flipping back around through the hole, or getting folded and crunched, but you can tack down the edges if you feel the need to.
The last step on these buttonholes is to rip out the basting seam holding the two edges of the binding together. However, just like how you don't want to cut your machine worked buttonholes until it's the point in the garment construction where you're adding the buttons, you don't want to rip the basting open until the very first time you need the buttonhole. Just trust me, everything is easier when it's all in one piece.
And there you go, you made a buttonhole on your machine and you didn't even need Presser Foot #3a
Okay, one last perk of this:
Have you ever tried to make a buttonhole on a knit? A lot of machines that do have a 1-step buttonhole give you one option for a worked buttonhole, and it doesn't really work on knits. Even the proper buttonhole for stretch fabric doesn't actually work super well. The problem is that you don't want buttonholes to stretch, or else the button will fall out, but stretch fabrics want to stretch, and they're difficult to stabilize.
Welllllll. Guess what we have the power to do.
When you go back to the step where you attach the facing into the buttonhole, you've now stabilized it on all four sides with a tightly woven fabric that won't stretch or distort. However, since the facing is pretty much only attached to the seam and the seam allowance of the buttonhole, it doesn't bunch or shift really badly, and makes some very neat-looking buttonholes. The buttonhole binding also is often a tighter woven fabric, making it easier to actually insert buttons into and to wear without damaging your buttonholes.
If you have a fabric that's very tightly assembled and doesn't fray or rip, like a 4-way stretch fabric or a polar fleece, and you need to do a buttonhole, you can actually even cheat more.
Just like before, stack your facing onto your garment, right sides together. Sew your little box, but in this case you want it to be as narrow as the physics of the fabric will actually allow. Do a couple of tests to make sure you know how much width you need to make is structurally work. Slash the box open, but you don't need to do the corners this time. Flip the facing through, iron the fuck out of it to make your buttonhole as small as possible, and then do some tacking to keep the facing where it should be. If you have enough room, you can sew the top and bottom to the facing like you did on the bound version.
You can topstitch or hand-overcast through the buttonhole to make the facing more secure. It would look like this except imagine if whoever made the buttonhole actually gave a shit. If you can't get this method to work right, oops, looks like you're going to have to do the method with the separate binding.
Do some tests, make sure you like how it looks and you like how it works.
Anyway, if your machine decides to get violent when you ask it to make worked buttonholes, or the fabric you're using doesn't allow worked buttonholes, or you just want to have some fun contrasting buttonholes, faced and bound buttonholes are here to save you.
