A method is provided for forming a feature on a needle. In particular, a hollow,
metal cannula has a first end, a second end and a substantially constant outer
diameter extending over at least a portion of its length. An annular metal sleeve
is provided that has a proximal shoulder and a distal shoulder. The length of the
annular sleeve is less than the length of the constant diameter portion of the
cannula. The sleeve has an inner diameter approximately equal to or less than the
outer diameter of the constant diameter portion of the cannula. Two edges extend
axially along the length of the sleeve, from the proximal shoulder to the distal
shoulder, thereby defining a slit. The sleeve is positioned on the cannula at the
constant outer diameter portion in an interference fit. An additional mechanical
junction may be provided to secure the sleeve to the cannula. For example, the
sleeve may be welded to the cannula using a laser welder at at least one edge of
the sleeve near one of either the proximal face or the distal face. Alternatively
and additionally, the sleeve may be crimped or glued to the cannula. In accord
with another aspect of this invention, a needle is provided made in accord with
this method.
