Threading top and bobbin without guessing
Okay. Last lesson we went over the parts. Now we're going to load thread into them, and this is the part where most people start guessing halfway through and just hope it works out.
Don't do that. Guessing is how you end up with a bird's nest of thread under the plate and no idea why.
Here's the thing. Threading a machine is not complicated, it's just sequential. Every step depends on the one before it. Skip one, and the machine will absolutely still let you sew, it just won't sew right. Then you're troubleshooting five problems when really you just missed step three.
Top thread first
Put your spool on the pin. If there's a little cap that goes on top of it, use it, it keeps the thread from bouncing around while it feeds.
Now follow the thread guides. Your machine has a path stamped or embossed into the top, usually with small arrows or numbers. Follow it exactly. Most people's instinct is to speed through this part because it looks obvious. It's not always obvious. There is almost always one guide people miss, usually right before the needle.
The part everyone skips: the tension discs. There are two little discs partway down that the thread has to sit between, not just near. You want the presser foot lever up when you do this. If the foot is down, the discs are clamped shut and the thread will slide past them instead of seating in. Your stitch will look fine for about four inches and then go haywire, and you'll have no idea why, because visually it looked threaded.
I know this because it happened to me. First month I owned my machine, it ate an entire seam into a knot under the throat plate, this thick tangled bird's nest, thread wound around everything down there. I didn't call anyone. I took the throat plate off myself, cleaned out the lint, cleared the feed dogs, and rethreaded from scratch, top to bottom, slow. Turned out the thread had never actually seated in the tension discs. The presser foot was up when I threaded it and I didn't know that mattered yet. Total rookie thing. But once I saw it, I never missed it again, and now it's the first thing I check on anyone's jammed machine.
Thread down through the take-up lever, that's the little metal arm that moves up and down while you sew, then down to the needle. Needle threads front to back, unless your machine says otherwise, check your manual for that one detail because it does vary.
Bobbin
Wind it before you thread the top, honestly, order doesn't matter much, but I like to get the bobbin sorted first so I'm not doing it with a threaded needle in my way.
Bobbin thread follows its own little path, usually a spring-loaded clip on the bobbin case. Drop the bobbin in so it unwinds in the direction the machine wants, there's usually a diagram etched right into the plate showing you which way. Pull it through the tension spring, not around it, through it.
Then bring the bobbin thread up. Hold the top thread with one hand, turn the handwheel toward you slowly until the needle goes down and comes back up, and it'll grab the bobbin thread and pull up a loop. Pull that loop out, and now you've got both threads sitting under the presser foot, a few inches of tail on each. Don't skip this. If you start sewing without pulling that bobbin thread up, you get a nest on the underside almost every time.
Test it before you trust it
Scrap fabric. Always scrap fabric. Sew a few inches and look at both sides of the seam. Top should look like a clean line of stitches. Bottom should look the same, not loopy, not puckered.
If it's off, that's not a mystery, that's information. The machine's telling you something. Loose loops on the bottom usually mean the top tension's off or it didn't seat in the discs right. Loops on top usually mean the bobbin's not threaded through its tension spring. Go back and check, don't just crank the tension dial and hope.
One opinion while we're here: change your needle more than you think you need to. A lot of the tension weirdness people blame on threading is actually a dull or bent needle. If you've been sewing through several projects on the same needle, swap it before you spend twenty minutes rethreading over and over for no reason.
Close enough isn't a setting. Thread it right, test it, then sew.
Before next time: thread your machine start to finish from memory, no notes, and sew a few inches on scrap. If it's not clean on both sides, don't fix it and move on, figure out which step you skipped.