- Use topstitching thread in your top spool, normal thread in your bobbin.
- You must use a topstitching needle (or a jeans needle). If you don’t do this, terrible things will happen. Never, never, never use a normal needle for topstitching with heavy thread, unless you actively enjoy frustration.
- Set your stitch length to be slightly longer than normal, I usually click mine up three lengths on my Bernina.
- Take a scrap of your fashion fabric and fold it in half. This is now your practice scrap. Keep it close. Before you topstitch a tricky seam, sew a practice length on your scrap. Much better to get this scrap all gnarled up than your beautiful project.
- If your thread gets puckered on top, lower the tension number to loosen it. If it’s too tight, set the tension a bit higher.
- Choose a consistent position for topstitching, and stick to it. I often line the edge of my foot up against the seam line as it’s the easy option, but if you have a fancy straight stitch or edge stitch foot you can use that.
- To prevent your machine from eating the fabric, pull the bobbin and top thread together at the start of every seam. There’s an excellent description of how to do this here.
- Topstitching stretch fabric can be ugly. If you’re sewing decorative lines on single thicknesses of fabric (like jeans pockets), iron some interfacing on the back, or they will stretch out to infinity.
Using a double needle – ninja level topstitching
- Double needle topstitching is tricky. You will need to test it every time you use it. This is where your scrap fabric comes in.
- Buy a special twin needle – you can get a 4mm one here in the UK. I wouldn’t recommend trying to mimic this by sewing two lines of thread, it’s incredibly hard to match them up perfectly.
- Every machine is different for twin topstitching, so check your manual. I thread the 2 threads exactly as I would with 1. I put the thread from the usual spool into the left needle, and the thread from the new spool into the right needle.
- You can only sew very gentle curves with a double needle, and you can’t turn and pivot. For jeans, the main issue will be the decorative topstitching around the fly. Draw in a smooth curve and practice it first on your test scrap.
General tips to minimise frustration
- Don’t be afraid to use the handwheel! Especially at the beginning and end of seams with lots of different layers, like the waistband.
- When your needle gets stuck, it can be temporary or it can be a sign of doom. To find out, gently rotate the handwheel back and forth. Sometimes you can coax it out – often by rotating it backwards. Sometimes you need to stop, unpick an enormous hamster’s nest of tangled threads, and start all over again (sorry).
- Topstitching will never feel as easy as normal sewing. Expect some reluctance from your machine. Learn to distinguish between the slow and reluctant feeling your machine makes when going over bulky seams, and the ‘help help I am stuck in the needle plate’ signal you get when things have gone very wrong.
- You might need to re-jig the pattern instructions to make topstitching seams easier. Here’s the order I sew jeans in.
- Arrange your pieces so you can do a period of normal sewing, then topstitch lots of seams at once. Otherwise you will go insane changing threads and needles and re-jigging tension.
- You should sew all your topstitching lines in one fell swoop. Stopping and starting in the middle never looks good. It’s very hard to match up the line of thread perfectly, especially with a double needle.
- Check the fit before you topstitch any seams. Unpicking that shiz is not fun.
- Buy a lot more topstitching thread than you think you need, especially if you are sewing jeans or doing double topstitching. 3 spools is the minimum for a classic 5-pocket jean style.
I’m not an expert by any means – this is just what worked for me. Let me know what I’ve missed out!