After coiling wire around a mandrel, thread your saw blade through
the coil to cut the jump rings apart, and saw from the inside out.
This makes sawing the coil easier as your blade tends to slid when
starting to cut from the outside of the coil. Brad Simon CMBJ
The best way we have found to make jump rings is to wind the wire
around a wooden dowel of the appropiate size and cut with a fine saw
blade held at an angle to the rings. Cut through the wood as you cut
the rings off. When held in a vise the wood gives good support when
cutting and the rings and they drop off onto the saw blade.
hold the dowel in the chuck of a screw gun, insert the wire in the
space between the chuck (perfectly safe), and wind at a slow speed.
use your thumb to keep the windings uniform.