Choosing Buttons & Making Buttonholes
A ligne is the international standard for measuring a button’s diameter. Domed, thicker, or handmade buttons may require a larger buttonhole. Variations in measurement often occur, so all button sizes should be considerate approximate.
If the button has a shank, the width of the shank also varies, and needs to be considered when determining the placement of the buttonhole on a garment.
The buttonhole needs to be large enough to comfortably accomodate the button. If it's too small, the buttonhole will eventually rip or the button itself will become detached (and maybe lost), and need to be replaced. If you've used one-of-a-kind buttons, you may have to replace them all. So err on the side of making the buttonhole a tiny bit larger if neccesary.
Generally, the length of a buttonhole is determined by the diameter of the button, plus 1/8". For ball, jeweled, or oddly-shaped buttons, it may be neccesary to allow a bit more. Always make a test buttonhole or two on a scrap of the garment fabric before hand, so you can set your thread tension, test the stitching, and make certain the button will go through the hole and stay in place once the garment is fastened.
If you're using a sewing machine that holds the button while making the buttonholes, I suggest that when using handmade buttons you make each buttonhole to a specific button, then make a little note of which goes where.
Garment Design and Construction:
When the center of a button is placed on the center line of a garment pattern block, half of it will extend to the right, and half to the left of the center. This makes it neccesary to extend the center edge. The width of the extension should equal the diameter of the button.
The buttonhole extends at least 1/16" to the left of the garment to allow for a shank button. If a button has a very wide shank, measure the shank and extend the buttonhole to the left of the center by half the measurement of the shank. The length of the shank does not change the size of the buttonhole.
On a neckline, with or without a set-in collar, the buttonhole is placed one-half the diameter of the button plus 1/4" away from the neckline.
A garment without a belt should have a button placed exactly on the waistline to maintain close fit. For coats or suits, the button may be placed up to 1/2" above or below the waistline if the overall appearance is improved.
For a garment with a belt, plan and mark the buttonholes above and below the waistline so that the belt or buckle will be at least 1 1/2" away from the buttons.
After determining the position of the neckline and the waistline, divide the remaining space by the number of buttonholes you want. On a woman's garment, try to place a button right at bust level to prevent the garment from gapping open.
Women's garments always button right over left.
A few more notes for better buttonholes:
~Don't skip or skimp on interfacing in this area. Use the same pattern piece for interfacing as for the fashion fabric where buttons and buttonholes will be placed, so the interfacing extends all the way to the edge of the fabric.
~To mark the buttonholes for stitching, trace them onto a piece of onion skin tracing paper, pin the paper to the fabric, and stitch through it. This is usually more accurate then trying to mark on the fabrics, and eliminates worry about whether the marks will be competely removable.
~Just before stitching the buttonhole, give the lines and the area around them a few small whacks with a hammer. Not too hard, just a quick smack-smack-smack will flatten and smooth that area so your sewing machine will run a little better.