-It is not adaptable (one wire diameter, one helix diameter, one step spacing)
-It is not completely precise (though you bent the helix *very* precisely, the wire has some spring effect and the shape of the helix will slightly change when you remove it from the winder)
But it is a great tool:
-If you have a few small pieces of wood and wood glue, the cost is just $0
-It need avout 10-15 minutes of work to build, you'll make it in less than an hour and spend most of that time waiting for the glue to dry
-Though the final dimension of the helix are not really precise, they are very consistant. The final helix looks perfect !
This Helix Winder has originally be made to bend wire for my DNA Lamp. (see link in the menu on the left)