Look at the back of a test stitch
Stitch a small test piece on scrap fabric. Look at the BACK. You should see ⅓ top thread and ⅔ bobbin thread. More top thread = top too tight. More bobbin = top too loose.
StitchPilot.aiTroubleshooting · Tension
Embroidery Machine Tension Problems
Tension issues show up as loops on the back of the design (top tension too loose), thread breaks (top tension too tight), or puckered fabric (general tension imbalance). This guide explains how to diagnose top vs bobbin tension and adjust correctly.
Tension diagnosis and adjustment
Adjust top tension first
Top tension is the easy fix — turn the tension dial ¼ turn at a time. Tighter for loopy back; looser for puckered fabric or thread breaks.
Check bobbin tension if top is calibrated
Bobbin tension is set at the factory but can drift. The "drop test": hold the bobbin case by the thread; it should drop slowly with a gentle bounce. Falls fast = too loose; doesn't move = too tight.
Adjust bobbin tension carefully
Bobbin tension screw is small. ⅛ turn at a time. Wrong way is easy — counter-clockwise loosens, clockwise tightens. Many embroiderers leave bobbin alone and only adjust top.
Common tension symptoms
Symptom → cause
Match your symptom to the most likely tension issue:
- Loops on the back: top tension too loose — tighten ¼ turn
- Top thread breaking: top tension too tight — loosen ¼ turn
- Bobbin thread showing on front: top tension way too tight, or wrong thread on top vs bobbin
- Puckered fabric: overall tension too tight, or wrong stabilizer
- Weak/loose stitches everywhere: top tension too loose
When tension keeps drifting
Bigger issues
If you adjust tension and it goes back to wrong, something else is up:
- Lint in the tension discs — clean with canned air
- Old or stretched thread — replace with fresh spool
- Bent tension spring — needs machine service
- Bobbin case scratched or damaged — replace
- Recent thread switch from polyester to metallic = needs different tension
Embroidery machine tension — common questions
How do I know if my embroidery tension is too tight or too loose?
Look at the back of a test stitch. ⅓ top thread visible and ⅔ bobbin thread = perfect. More top thread visible = top too tight. More bobbin thread visible = top too loose.
Should I adjust top or bobbin tension first?
Top tension. It's easily adjustable and where 90% of tension issues live. Bobbin tension is set at the factory and only needs occasional fine-tuning.
Why does my fabric pucker around the embroidery?
Usually overall tension too tight (try loosening top ¼ turn) or wrong stabilizer for the fabric. Cut-away medium for most embroidery; stretch fabrics especially need cut-away.
How often should I check embroidery machine tension?
Every time you switch thread brand, thread weight, or fabric type. Tension that works on cotton polo may be wrong for terry towels. Quick test stitch on scrap saves hours.
Can I damage my machine by adjusting tension wrong?
Top tension dial: no, just produces bad stitches until you readjust. Bobbin tension screw: yes, you can lose the screw or strip the threads. Adjust bobbin tension in small increments and keep the screw seated.
Eliminate the design
Check the file in StitchPilot.ai first
If the design looks normal in the viewer, your tension issue is on the machine side — much easier to diagnose.
Verify the design first →