What is a Tension System?

Description

The tension system is the mechanism controlling how tightly scissor blades are held together at the pivot. Types include flat spring, ball bearing, and sealed bearing systems. Correct tension means blades close smoothly under their own weight from half-open position.

What is a Tension System?

The tension system is the mechanism controlling how tightly scissor blades are held together at the pivot point. Types include flat spring (basic), ball bearing (smooth), and sealed bearing (premium). Correct tension means the blades close smoothly under their own weight from a half-open position. Too tight causes hand fatigue; too loose causes hair folding.

Why It Matters for Scissors

Tension directly affects three things every stylist feels: hand fatigue, cutting precision, and edge longevity. A stylist opening and closing scissors 500-800 times per client, across 8-12 clients per day, accumulates thousands of repetitions. Even a small increase in resistance from over-tightened tension compounds into significant fatigue and potential repetitive strain injury.

Hikari Scissors popularized a memorable tension test: the scissors should be adjustable using a 10-yen coin (approximately the size of a US penny) inserted into the tension screw slot. This ensures the adjustment mechanism is accessible without specialized tools, allowing stylists to fine-tune tension throughout the day as conditions change.

The standard test for correct tension is the “drop test.” Hold one handle with the scissors open to 90 degrees, tips pointing up, and release the other blade. It should fall smoothly under its own weight, closing to approximately 70-80% before stopping. Full closure indicates too-loose tension. Minimal movement indicates too-tight tension. Most manufacturers recommend this test as part of daily scissor maintenance.

Technical Detail
There are four main tension system categories used in professional scissors, each with distinct mechanical properties. **Flat screw systems** are the simplest: a bolt passes through both blades, and a nut on the opposite side is tightened or loosened to adjust tension. A flat washer between the blades controls friction. This system is inexpensive and reliable but requires frequent adjustment as the washer wears. Found on most scissors under $150. **Leaf spring systems** add a flat metal spring between the tension nut and the blade. The spring provides consistent tension even as components wear slightly, reducing the frequency of adjustment. The spring absorbs small variations in tightening torque, making the scissors more forgiving of imprecise adjustment. Common on mid-range scissors ($150-$400). **Ball bearing systems** replace sliding friction between the blades with rolling friction by inserting a ring of small steel balls around the pivot. This reduces opening/closing resistance by 40-60% compared to flat washer systems. The bearings must be kept clean — hair debris between the balls increases friction and can cause uneven tension. Used on premium scissors ($300+). **Sealed bearing systems** enclose the ball bearings in a protective cartridge, preventing contamination from hair, water, and chemical products. These systems maintain consistent tension for longer periods between adjustments and are effectively maintenance-free at the pivot point. The sealed units are typically replaceable, though the replacement must be performed by a trained technician. Found on high-end scissors ($500+). Some manufacturers use proprietary tension systems that combine elements. Mizutani's UFO (Universal Flat Offset) system uses a disc-spring mechanism that maintains constant blade pressure across a wide range of screw positions, making over-tightening nearly impossible. This self-regulating approach is particularly valuable for stylists who are not accustomed to checking and adjusting their tension regularly.

Sources

Frequently Asked Questions

Open the scissors to 90 degrees, hold one handle with the tips pointing up, and let the other blade fall. It should close to about 80% and stop. If it swings fully shut, tension is too loose. If it barely moves, tension is too tight.

Yes. Too-tight tension forces the blades against each other with excess pressure, accelerating edge wear. Too-loose tension allows hair to fold between the blades instead of being cut, which can also damage the edge by creating micro-chips from uneven loading.

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