ramé-hart fabricates a variety of custom coaxial and triaxial needles for a wide spectrum of special applications. Some of our customers use ramé-hart triaxial needles for electrospinning and electrowetting applications. The needles have excellent electrical conductivity. They are also used for specialized surface science measurements (such as measuring surface dilatational elasticity and viscosity, surface tension on drops and bubbles, and mixing liquids at the point of measurement).
Shafting is precision Type 304 Stainless Steel while the Luer connector is nickel and chrome-plated brass. These needles are autoclavable; they can be cleaned, washed, boiled, sterilized, and reused many times. Many options and tubing sizes are available to fit any application.
We now offer a prebuilt triaxial needle. See http://www.ramehart.us/prebuilt-triaxial-needle/
1. Download the needle chart here: http://www.ramehart.com/pdf/needles.pdf to help you determine which gauge needles you require. This chart shows the ID (inside) and OD (outside diameters) for all standard needle gauges. For triaxial needles be sure that the OD of the middle needle you choose is smaller than the ID of the outside needle and that the OD of the inner needle you choose is smaller than the ID of the middle needle. Note that currently we are not fabricating any coaxial or triaxial needles with an inside needle greater that 28 gauge.
2. Download our triaxial needle design worksheet here: http://www.ramehart.com/pdf/triaxial_worksheet.pdf Figure out your inside, middle, and outside gauges along with connector type for the side fitting (A or B style). Figure out the other dimensions per your requirements as indicated on the worksheet. Please note that innermost needle must be 28g or lower.
For examples of some of the custom triaxial needles we have manufactured, please see our flickr page.
Note that standard delivery time for this item, since it is custom made, is one week.