Buttonholes are some of my least favourite things to do, but bound buttonholes look so beautiful (like on my Swing Coat) that they are a necessary evil. They can be pretty complex and fiddly, but I find that sewing them by hand gives you much more control over the fabric.
First things first (I'm the realest), cut a thin strip of fabric to measure your button. Pin and measure the distance from the pin to the fold. Add 1/8 inch and that is the width of your buttonhole! On your fabric baste horizontally where your buttonhole will sit and vertically the width. Most patterns will mark where the buttonhole needs to begin, but if you're working without a pattern place the buttonhole so that the centre front is about 1/4 inch inside on the right. I'm using white thread for basting and pale blue thread for the permanent stitches so it's easier to see.
Next cut the welt that will form the buttonhole. Make this 2 inches by 1.5 inches longer than your buttonhole. I like to fold mine horizontally and use that as a guide for my horizontal basting. On the wrong side, place your interfacing. I use raw silk for my interfacing and stabilising, I prefer it over iron-on which I can never use without melting glue on my iron. Sew a rectangle with the left and right edges at your basted buttonhole widths. The thickness of your rectangle will depend on how big your button is, the thickness of your fabric, and also the style you want. I use a backstitch on this to make sure it's very strong. Clip down the middle and snip little notches into the corners (but not too close).
Push the welt through the hole from the right side to the wrong side. Then working from the the wrong side, fold one half of your welt up so it covers the opening. Fold it back down again so that half of the opening is covered. I find that if I match up the edge of the welt with the little clipped edge of the opening it's usually a bit easier. Pin in place and do the same on the other side.
Turn back over to work on the right side and use stab stitch along the seam of the welt. This is going to hold the welt in place. Do the same for the other side. Grab the little triangle notches and give them a sharp tug, this gets any fabric out of the way of the welt. Stitch the notch to the welt. I like to use an overcast stitch for extra strength.
Finally, stitch the sides of the welt together to hold them in place and trim around the welt to make it an oval shape. Press the buttonhole and you are done!
I hope this helps anyone having trouble or wanting to see a hand-sewn version rather than machine sewn. Good luck!
I tried to make bound buttonholes, which I haven't done since I was 15. I have fast remembered why that is the case. I think it does look pretty though, so the effort was worth it!
Rarely seen these days unless on luxury or vintage...
I've been practising on making these and although they are not as hard as you may initially think it does need to be finished by hand on the reverse to maintain the beauty of it, so they are time consuming (especially for the perfectionist!) but look how pretty it is!
I like how it looks old-fashioned / old school techniques - let's not forget them...