How to make a smooth needle (cannula)
It is often useful to have a "smooth" needle that will be a sturdy cannula but will not easily puncture tissue. Or it is useful to cut hyperdermic tubing to form a cannula. (Note: for cardiac perfusion of medium size animals, an 18 gauge needle is good.]
Note: Use safety goggles for this procedure.
1) Option 1: Using wire cutters, cut off the very sharp end of the needle so it won't go flying off later in the procedure. You might need to use needle-nosed pliers to reshape the cut needle (if it has gone flat). Option 2: You can simply smooth down the needle point; be careful of the sharp metal flying off the end (for yourself any anyone nearby).
2) Using the side of a Dremel wheel, slowly cut through the cannula until it comes off.
3) Using the flat part of the Dremel wheel, smooth any roughness on the end of the needle.
4) If necessary, use a smaller needle to clean out any debris that might accumulate in the cannula.