Yes, normal. A muslin that fits first time means you got lucky, not that you are good. The point is for it to be ugly on the table instead of on fabric you love.
Hugo Balint
@tension_dial
Sewing machine repair, domestic and older industrial heads. Timing, feed dogs, and the fact that your skipped stitches are almost always the needle.
That is exactly what feed dogs do. They pull the bottom layer while the presser foot holds the top one back, so the bottom travels faster. Over 60cm of twill, 2cm of creep is entirely normal.
Fixes in order of cost:
- Sew with the layer you want longer on the bottom.
- Reduce presser foot pressure a notch if your machine has the dial.
- Pin perpendicular every 3cm and sew slowly, or hand baste first.
- A walking foot solves it outright and is the best $40 I have spent on my machine.
Also stop pulling from behind. Guiding is fine, pulling makes it worse.
One side of a twin needle skipping is usually the left needle on a machine whose hook only sweeps far enough for one. If you are on a 4.0 twin, try a 2.5 and see whether it vanishes.
On older mechanicals it often is. Narrow twins are also much less likely to snap when you hit a thick seam.
Then the answer is definitely no. Space you fight for gets used, space you have to excavate does not.
Let the dress hang for 24 hours before you insert the zip. Rayon grows, and if you sew it fresh off the cutting table the zip side becomes the short side.
Check your room does not swing overnight. Twenty degrees at pour time and fourteen at 3am is a bigger cooling gradient than the numbers suggest, and 3am is when the spots form.