A needle's thinness is highly variable and depends on its intended use. The diameter, and therefore thinness, is typically specified by its gauge number, with smaller gauge numbers indicating thicker needles and larger numbers indicating thinner needles.
Needle Gauge and Thickness
The provided reference, a Needle Gauge Chart from Hamilton Company, shows the relationship between gauge number, outer diameter (O.D.), and wall thickness for several common hypodermic needles:
| Gauge Number | Needle Nominal O.D. (mm) | Needle Wall Thickness (mm) |
|---|---|---|
| 26 gauge needle | 0.464 | 0.102 |
| 25s gauge needle | 0.515 | 0.178 |
| 25 gauge needle | 0.515 | 0.127 |
| 24 gauge needle | 0.566 | 0.127 |
As you can see, a 26-gauge needle has an outer diameter of 0.464 mm and a wall thickness of 0.102 mm, while a 24-gauge needle is thicker. Other sources mention "extra thin wall" needles, further demonstrating the wide range of thinness. For example, the mention of 29g extra thin wall needles indicates even thinner needles are available.
Factors Affecting Needle Thinness
Several factors influence a needle's thinness:
- Intended Use: Needles for delicate tasks like embroidery or insulin injections are much thinner than those used for medical procedures like biopsies.
- Material: The material of the needle can also affect its overall thinness and strength.
- Manufacturing Techniques: Advances in manufacturing allow for the creation of very thin needles with strong walls.
Examples of Thin Needles
- Insulin Pen Needles: These are designed for minimal discomfort and often utilize "extra-thin wall" technology.
- Embroidery Needles: These needles need to be thin enough to pass through fine fabrics easily.
- Medical Needles (e.g., biopsy needles): While some medical needles are thick, there are also very thin ones designed for minimally invasive procedures.
