Pin it, measure twice, then sew
Okay. Last lesson we went over needles and thread and getting through thick seams without your machine throwing a fit. Today we slow way down, because this is the lesson people skip in their heads even when they're doing it with their hands.
Pinning.
I know. It feels like the boring part standing between you and the actual sewing. I get why people rush it. But here's the thing, pinning isn't optional and I don't care that it's slow. Every crooked seam I have ever fixed for someone traces back to a pin they didn't bother with, or a measurement they eyeballed because it looked close enough. Close enough isn't a setting on this machine. It's not a setting on any machine.
Why denim especially
Denim's forgiving in a lot of ways, we talked about that. It doesn't fray at you the second you look at it wrong, it holds a crease, it takes a beating. But it's also thick and it's got a weave that wants to shift on you while you're feeding it through. Two layers of denim under the presser foot will slide against each other if you let them. Pins stop that. Clips work too if you've got them, especially on a really thick double layer where a pin fights you, but for most of what we're doing today, pins are fine.
The actual steps
You're going to take your cut denim pieces from a couple lessons ago, whatever you're building toward, a patch, a bag panel, a hem. Doesn't matter for today. What matters is the process.
1. Lay your pieces right sides together, edges lined up. Not close. Lined up. Run your finger down the raw edge and feel for where it doesn't match. Denim has a little give to it and it's easy to let one layer creep ahead of the other.
2. Measure your seam allowance before you pin anything. Use your ruler, mark it if you need to with a fabric pen or even a sliver of chalk. Don't trust your eye yet. Eventually you'll eyeball a quarter inch just fine, but not today, and definately not on a project you care about.
3. Pin perpendicular to the edge, not parallel to it. Pins going the same direction as your seam are the ones that get run over by the needle, and that's how you either break a needle or throw your timing off. Perpendicular pins you pull out right before the foot gets to them.
4. Space them every two to three inches on denim. Tighter than that is overkill, denim holds its shape. Wider than that and you'll get shifting in the middle you don't notice until you've already sewn it.
5. Measure the whole thing again before you sew one stitch. Yes, again. Pull your ruler back out, check both ends, check the middle. This is the "measure twice" part and I mean it literally, not as some saying. I've said this in every module because it's true in every module.
6. Sew slow over the pinned section, and pull pins as you go, don't sew over them. I know some people sew right over pins and get away with it for years. I'm not going to be the one who tells you that's fine when it eventually snaps a needle into your hand.
On backstitching, since we're here
For a lot of this upcycling work, casual seams, a patch pocket, a bag lining, you don't need to backstitch like it's a wedding dress. A couple forward stitches at the start and a good knot at the end holds fine. Save your backstitching for actual stress points, corners, anything that's going to get pulled on or sat on. I know that's not what every tutorial says. I've thought about it and I still think it.
A quick story on why I harp on this
My machine ate an entire seam into a bird's nest under the plate the first month I owned it. Full tangle, thread wound up underneath like a rat's nest, machine wouldn't move. I didn't call anyone, I took the throat plate off myself, cleaned the feed dogs, rethreaded the whole thing from the top. Took me an hour of being annoyed at myself. Turned out the thread had never actually seated down in the tension discs, and the presser foot was up the whole time I was threading it. Rookie thing. The point is, I could've avoided the whole mess by slowing down at the start instead of rushing to get to the sewing part. Pinning and measuring is the same lesson wearing a different hat.
One caution
Watch your fingers when you're pulling pins mid-seam, especially with denim because you're pushing a little harder to get the machine through it and your hand's closer to the needle than you think. Pull the pin, don't yank it sideways, and keep your fingers back from the foot.
Before next time
Cut and pin a small denim test seam at home, measure it twice before you sew, and bring it in even if it's not perfect. I want to see your pin spacing, not a finished project.