How to Check and Adjust Scissor Tension — A Stylist's Guide
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Scissor tension is one of the most overlooked aspects of scissor maintenance — and one of the most impactful. Incorrect tension causes everything from hand fatigue and uneven cuts to premature blade wear and even dropped scissors. This guide explains how scissor tension works, how to test yours in seconds, and how to adjust it correctly.
What is Scissor Tension?
Tension refers to how tightly the two blades are held together at the pivot screw. It controls:
- Resistance: How much force is needed to close the scissors
- Blade contact: How well the two cutting edges pass against each other
- Balance: Whether the scissors feel natural and controlled in your hand
Too tight, and the scissors are hard to close, causing hand and wrist fatigue over a long day. Too loose, and the blades don't make proper contact, causing hair to fold between them rather than cutting cleanly — leaving frayed, rough results on your client's hair.
The 45-Degree Tension Test
This is the standard method every professional scissor technician uses. It takes about three seconds:
- Hold one handle of the scissors between your thumb and forefinger, blades pointing upward
- Open the other blade (or let it fall open naturally) to approximately 90° from the closed position
- Release the moving blade without any additional force
- Watch where the moving blade settles on its own
Reading the result:
- Blade falls to 45° and holds: Tension is correct. The blade swings freely but has enough resistance to stop at roughly 45°.
- Blade falls shut (past 45° or fully closed): Tension is too loose. The blades won't make proper contact through the full cut — hair will fold.
- Blade barely moves or stays near 90°: Tension is too tight. You're working harder than necessary and risking repetitive strain injury.
If you're working with thinning scissors, the test is slightly different — they should fall a little further than cutting scissors due to the lighter serrated blade. About 30–40° is usually correct for thinners.
How to Adjust Scissor Tension
Most professional hairdressing scissors have an adjustable tension screw — usually visible as a flat-head or cross-head screw at the pivot, sometimes covered by a decorative cap or knob. On some premium scissors, the tension is adjusted with a coin, a small wrench, or a dedicated key included with the scissors.
Tightening Tension (if blades fall shut)
- Identify the direction of your tension screw — look for a flat slot or cross pattern
- Turn the screw clockwise (right) in very small increments — a quarter-turn at a time
- After each adjustment, repeat the 45-degree drop test
- Stop when the blade settles at 45°
Loosening Tension (if blades barely move)
- Turn the tension screw counter-clockwise (left) in very small increments
- Test after each quarter-turn
- Stop when the blade settles at 45°
Important Cautions
- Never over-tighten: If the screw is already tight but the tension still feels wrong, the issue may be in the pivot mechanism (corrosion, debris), not the screw setting. Don't force it.
- Turn in small increments: A full turn of a tension screw is a dramatic change. Quarter-turns are the right unit of adjustment.
- Some scissors require tools: High-end scissors with tension keys or coin-adjusted screws should only be adjusted with the correct tool to avoid damaging the screw face.
- If the screw spins without engaging: The thread may be worn or stripped. This requires professional repair — contact your scissor sharpener.
Tension Changes Over Time — Why This Happens
Even correctly-set tension will drift over time. Several factors cause this:
- Normal wear: Metal-on-metal contact at the pivot wears very slightly with each cut. Over months of daily use, this can loosen tension gradually.
- Corrosion: Product and moisture at the pivot can cause the screw to seize or the metal surfaces to pit, changing how the blades pass each other.
- Physical impact: Dropping your scissors on a hard floor can jar the tension screw loose or change blade alignment in a single incident.
- Temperature: Metal expands slightly with heat (like a hot blow-dry station), which can make scissors feel temporarily tighter in warm conditions.
This is why checking tension every week takes three seconds and saves you from cutting poorly for months without realising the scissors are the problem, not your technique.
Tension vs. Blade Alignment — Understanding the Difference
Tension and blade alignment are related but different problems. Tension controls resistance. Blade alignment controls whether the blades actually pass each other correctly along their length.
A scissor with correct tension but poor blade alignment will:
- Push hair aside at certain points along the blade rather than cutting
- Feel like it "grabs" at a specific point when closing
- Show a visible gap between the blades when held up to light (they shouldn't have a gap along the cutting edge when closed)
Blade alignment problems cannot be fixed by adjusting the tension screw — they require the blades to be realigned by a professional sharpener. If your scissors feel off even after correctly setting the tension, alignment is likely the issue.
How Tension Affects Your Sharpening Schedule
Scissors running with incorrect tension — usually too loose — wear their cutting edges faster because the blades aren't contacting correctly. Instead of a clean shear action, loose scissors cause micro-flexing of the blade tips with each cut, which dulls the edge more quickly than proper use.
Keeping your tension correctly set is one of the best ways to extend the gap between professional sharpenings.
At ShearGenius, we check and set tension on every pair of scissors we sharpen as part of the standard service — no extra charge. If you're in Victoria, Tasmania, or South Australia, book a mobile scissor sharpening visit and we'll come to your salon.
Quick Reference: Scissor Tension at a Glance
- Test method: Hold one handle, release the other from 90° — it should settle at 45°
- Too loose: Falls past 45° — tighten screw clockwise in quarter-turns
- Too tight: Barely moves — loosen counter-clockwise in quarter-turns
- Correct: Settles at ~45°, smooth action, no resistance feeling in hand
- Check frequency: Weekly — takes 3 seconds
- Professional check: Every sharpening visit