Seam Allowances + Sewing Rounded Edges
It can be a little tricky when you are first starting out, but there are a few tips that can help you get the hang of it. Some of them apply to sewing straight seams as well.
- First, and for all sewing, watch the edge of the fabric against your seam allowance guide, and not the needle.
- Another question mentioned seam allowance being “set wrong.” If you have an adjustable seam guide, measure the distance from the needle to the guide, and adjust it so that it matches your seam allowance. Especially for straight seams, make sure that the guide is aligned parallel to the feed dogs, perpendicular to the front of the machine bed, otherwise your seam can be crooked. If your machine has seam guide lines printed or engraved on it, measure out from the needle to see which one matches the seam allowance for your project.
- For curved seams, go slowly. If the curve is steep, it may help to stop with the needle down, lift the presser foot and pivot the fabric a small amount. Set the foot back down and continue on. You can do this as often as you need to.
- Remember that if you are sewing a rounded edge, only the part of the seam allowance directly across from the needle should be aligned with the seam guide at any one time. Don’t try and stretch or bend the fabric around. Just sew slowly and only worry about the part of the curve that is about ready to go under the needle. Steer the fabric gently using both hands.
Finishing Fabric Edges
I love that someone asked a question about when to finish fabric edges and whether it depends on the type of fabric. It depends on the fabric, and also what part of the garment or project you are working on, and whether the edges there are likely to fray.
- The cut edges of most woven fabrics will unravel if they are exposed to wear. Edges cut on the bias won’t fray as much. Most knit fabrics don’t unravel, but some will run (like stockings). You can check how prone to fraying or running your fabric is on a scrap, by rubbing the edge with your thumb. If the fabric is a knit, stretch out the edge and watch what happens to the threads.
- Adding some kind of stitching to hold the threads at the cut edges together is called overcasting. You can use any number of machine stitches for this. I like to use a zigzag that that takes a few stitches to go from one side to the other. A regular zigzag stitch works too. Test the length and width settings to see that it’s not puckering the fabric. If your machine doesn’t have zigzag, use a line of straight stitching fairly close to the edge of the seam allowance. If you are overcasting a knit fabric, use a stitch that has some stretch, ideally as much as the fabric stretches in the direction you are sewing. Keep in mind that if you want to press your seams open, you will need to finish each side of the seam allowances separately.
- Most overcasting in ready to wear uses a serger, and you can too if you have one.
- Other alternatives for finishing edges include covering them with bias strips or seam binding, or sewing an enclosed seam (like a French or flat-felled seam). You can also use pinking shears (those scissors with sharp diagonal teeth) on the edges. They cut the fabric in little diagonals that are less likely to unravel, since they are on the bias. I may be a little on the paranoid side about this, but I wouldn’t use pinking shears alone unless I knew that the edge I was finishing would not get a lot of wear.
- I choose whether to finish the edges and how based on the fabric type and how much wear a seam will be exposed to. If I am making a special project, I may choose French seams or seam binding instead of overcasting, so that the inside looks clean. For most of my garment sewing (with woven fabrics) I overcast all the seams, except ones that will be enclosed in fabric (like inside a waistband, hem, or yoke). For knit fabrics, I don’t usually overcast the edges at all. However, I recently made a shirt from a silk knit that ran very easily, so I definitely overcast those edges!
- Usually I finish the edges after sewing the seams of a project. That way any adjustment or seam trimming happens first, and I make sure that I haven’t distorted the edges of the fabric pieces before sewing them together. Sometimes I will make an exception, like for the silk knit I mentioned. With narrow seam allowances and slippery fabric, I was afraid that I would get runs in the edges as I sewed them together, so I overcast them first. If you decide to do this, test on scraps and adjust your settings to make sure that your overcastting method won’t distort the fabric edges, which could throw off your seams or cause the fabric to pucker.
Sewing Slippery + Stretchy Fabrics
Several people asked variations on this question about fabric slipping, sewing knits and using a walking foot or a serger, which are all related. Although this is a little bit outside the scope of “beginning” sewing, it’s obviously something you all want to know, and I hope that by adding some tips here I will help you try out some different fabrics with less frustration!
No amount of pins will hold the fabric perfectly still, and too many will get in your way. Put a pin at the top of your seam, then at the bottom, then in the middle, then in the spaces in between, so that you keep the fabric layers even.
The Feed Dogs + a Walking Foot
The feed dogs always pull a little more on the layer of fabric they directly contact than on the layers above. This is especially apparent in slippery fabrics and knits, and across long seams. It also shows up in quilting, since there are a lot of fabric layers. (By the way, if you are sewing two pieces together, and one layer is larger than another, you can use this effect to help you ease and make the two layers match, by turning your project so that the larger layer is on the bottom as you sew.)
A walking foot, which has teeth on top to match the ones in the feed dogs, is designed to help even out the pull on the top layer of fabric. You can get a walking foot especially for your brand of sewing machine, or a generic one to fit your shank type, which is usually cheaper and works fine. I love my walking foot, and I almost always use it when I’m sewing with knits and slippery fabrics.
Stitches and Settings + Sergers
Different stitch selections, lengths, and widths can push or pull the fabric more or less than you want as you sew. A serger has two sets of feed dogs, and a special setting to adjust them called differential feed. This lets you adjust the feed to gather in the fabric more or less, which is a big reason why many people love sergers for sewing knits. However, on every project I’ve made so far, I’ve been able to adjust the settings on my regular zigzag machine to get a result I’m happy with. That’s why I still don’t have a serger! If you’re trying out a new fabric or want a particular effect, make as many samples as you need to to figure out what settings will work best. On the silk knit (a new fabric for me) I made a whole bunch of little test seams. I found that by increasing the stitch length, I got the machine to gather the fabric in more, so I could adjust the stitch length until the seams were not too gathered or stretched out.
Basting + More Options
For difficult seams that don’t want to stay in place, my ultimate solution is basting. That means using some temporary stitches, sewn either by hand or by machine, to hold things in place. Basting by hand is slower but gives you the most control. By machine, use a long stitch length to make it easier to pull out the basting later. Sew close to your intended seam line. Just concentrate on keeping the fabric edges where you want them, and don’t worry about how the basting stitches look. Pull out some of them if you need to and try again, until the fabric is held where you want it. Then sew your seam with regular stitching. The basting will hold everything together better than pins, and you won’t have to stop to pull them out or worry about them distorting the fabric. When you are happy with your seam, pull out the basting stitches.
Some people also sew with a layer of tissue paper, or use water-soluble stabilizers and/or fusible web when sewing and hemming tricky fabrics. I don’t have any expert guidance there; I’m kind of a purist when it comes to fabric and thread. But those options are also there for you to explore.
I really wish I had time and space to answer every single question you posed! I will finish off by giving a quick answer to two more which are more in-depth than I can answer fully here, but important, and I can at least point you towards some more resources.
The quick answer to “What is interfacing?” might be: anything that stiffens or stabilizes a layer of fabric. You might want something lightweight to make a shirt collar crisp, or much heavier for the bottom of a purse. Many people think fusible when they think about interfacing, and there are all kinds of weights and types that you can iron on to reinforce any kind of fabric. You can also use any kind of fabric or sew-in interfacing that produces the effect you want. Lately I have been using a simple densely woven, somewhat stiff cotton fabric from my stash to interface the waistbands of all my pants and skirts. Try out a sample, either sewing or fusing it on to a fabric scrap, to see how your chosen interfacing changes the hand of your fabric. The most extensive selection of interfacing I know of is at Fashion Sewing Supply.
This is a huge topic, and one that I’m definitely still learning myself. I think everyone who sews clothes would say the same!
Unfortunately, the quick answer to “Is there an easy way to increase the size of a pattern?” is no. Those lines on the pattern for different sizes are created by grading, which is a system that patternmakers have worked out. You’ll notice that the amount graded is different in different places on the pattern pieces, which can make it quite complex to scale the pattern up, depending on how many pieces are in the pattern and how complex they are. I would suggest starting with patterns that are available to fit your measurements. Then when you get a little more experience, you can try grading up a pattern you like, or altering one that fits you to get a similar style. Of the more independent pattern companies (which I love to support), I know that Cake Patterns go up to 50” waist, Hot Patterns include up to a 44” waist, and some styleARC patterns include plus sizes.