What is Micro Stainless Steel Tubing?
Aug 25, 2023
What is Micro Stainless Steel Tubing?
Micro, or miniature stainless steel tubing is widely defined as “needle tubing”, or tubing whose outside diameter falls within the range of hypodermic tubing. The largest tube OD for hypodermic tube is .259” OD. Standard hypodermic, or “hypo” tube is defined by the Stubs Iron wire gauge (aka Birmingham gauge system), where gauge numbers correspond to different tubing outside diameters. These micro tubing gauge numbers are inversely associated with the tube outside diameter, so the higher the gauge number, the smaller the stainless steel tubing outside diameter. There is not a proportional or formulaic relationship between gauge sizes on micro tubing. These hypo/micro gauge sizes are simply a long established standard still widely used today.
Importance of Gauge Sizes
A practical example of gauge sizes relates to needle use in medical settings. 16-18 gauge needles are often used for blood drawing (lab or blood donation), whereas 22 gauge and smaller gauges are used for injecting vaccines, medicines etc. This makes sense because the lower gauge number needles have larger outside diameters and inside diameters and are able to flow a larger volume of fluid, whereas the amount of fluid transfer on a vaccination is much less. Thus, a higher gauge number (but smaller OD) needle can be used for vaccinations. A smaller needle, all other features being equivalent, is less painful because it induces less trauma to the skin.
Micro stainless steel tubing in the sub .259” OD range can easily be manufactured to customer specific OD’s, ID’s (inside diameter) and walls, as well as custom tolerances. Manufacturing custom micro tube can often be done quickly on small runs, and once a process is established can be readily scaled up to production volumes.