Twin Needle Topstitching on Denim

Twin Needle Topstitching Tips and Techniques

Now with a few how-to videos.

Twin Needle topstitching on denim adds a professional touch to many of the garments I sew.  This post is a result of my experience and experiments.  I taught a lecture-style class at the CreativFestival about twin needles a year ago, and quickly realized how knowledge-hungry we as sewists are.

Twin Needle Topstitching on Jeans

Here is a pic of the twin needle I use for all my jean topstitching. 

About the Needle

One shaft, 2 needles, 6 mm apart.  The 100 refers to the needle size (big, 18 in old numbers) and they have nice large holes, perfect for thick top-stitching threads.  My Husqvarna/Viking sewing machines take this 6mm spacing easily, but check your manual if you have another brand.

If the holes in the needles are too small for your thread, it will shred and break as you sew.  Not fun. Or your needle could break.  Even less fun.

About the Thread

My very favourite topstitching thread is cotton, made by Sulky and it’s a “12 weight”.  It’s thick, but soft.  I used to sell it when I owned my store, so I have a “bit of a stash”, lol, but it’s getting low.  I was delighted to see that here in Canada “The Great Notion” in B.C. is carrying it, and I’ve linked to it here.  There are plenty of colours to choose from, and you only need one 330 yard spool.  Wind some off onto a bobbin and use that for threading the second needle.  Sulky also makes a 30-weight cotton, and 30 and 40 weight rayon that are suitable for topstitching.  There are many other brands that make similar threads, these are the ones I am accustomed to.  Don’t be afraid to experiment.

I like to use colour in my topstitching, after all, what’s the point if nobody can see it.  Like store-bought jeans.  And why not use 2 different colours?

I use regular sewing thread in my bobbin which will zig-zag underneath as the twin upper needles straight stitch.

Machine Set-Up and Threading

It’s important to use a zig-zag throat plate AND a zig-zag presser foot which has a groove underneath to glide over the raised seam with no resistance.  Here’s a pic of my throat plate and the groove in the foot.  On Husqvarna/Viking machines it’s a “B” foot.  Check your manual for other brands.

Consult your manual for the correct thread path.  On one of my machines, the left thread comes off the spool clockwise, and the right thread comes off counterclockwise.  The right thread also bypasses the thread guide on the needle-bar. If you don’t thread correctly you run the risk of tangles and needle breakage.

If your machine has a “safety setting” for twin needles, USE IT!  It prevents you from selecting a needle position where the needle will hit your throat plate.  Twin needles are expensive!

Lengthen your stitch for topstitching. I use 4mm. 

The zig-zag on the underside acts as a fabric finish, preventing fraying.  Keep this in mind as you plan your sewing strategy.

Sample: 2 layers of denim. Sulky 12 wt (blue) in needles, 50 wt in the bobbin, stitch length 4mm.

Sewing Techniques

Twin needle topstitching with thick thread is not the place for using a back-stitch to anchor your thread.  If your machine has an automatic “FIX” disable it.  If the beginning and/or ending is going to be in a seam allowance just leave a bit of a tail of thread.   However, if you’re using a twin needle stitch to attach a pocket,  or something similar, start and end with long thread tails so you can anchor them down on the inside by hand.

Curves and Corners

Curves just take practice, slow and steady.

Here’s a video of me twin needle top stitching along the faux-fly.

A 90 degree corner is the neatest, and here’s how it’s done.  Following the orange arrow in my pic, stop at the double orange arrows with the needles UP. Hold your fabric so it doesn’t move, and raise the presser foot.  Rotate the fabric 90 degrees to the right, (clockwise) lower the needles into the fabric where the blue arrows indicate.  Lower the presser foot and sew.

Time to practice that twin needle topstitching on a double-layered scrap!

Practice gentle curves, 90 degree corners and sewing straight then as a top-stitch beside a sewn seam with the seam allowances going left underneath, and then right underneath.  Keep that needle just a hair away from the seam line.

Test sewing both with the grain and across the grain, the amount of stretch in your denim could affect the look of your stitching.  Often though, a quick blast of steam from your iron will tame a slight ripply look.

Sample: seam sewn with a straight stitch, seam allowance pressed to the right.  Twin needle 6.00/100, 12 wt Sulky in needles 50 wt poly in the bobbin, stitch length 4mm.

Here’s a short video showing how I use a tool to keep my presser foot level when crossing thick seams, preventing broken needles.  (and saving money)

This (edited) post is part of what my Eleonore Sew-along participants are getting.  Registration for the sew-along is closed, but the complete set of notes will be available for sale after my sew-along is complete, near the end of September.

I shared some of this information in a previous post, click here to read that one.

I hope you find this info interesting and useful, feedback is always welcome! 

Email me at yvettechilcott at yahoo dot ca