Flexible Axis Revolving Tool-holder

The Flexible Axis Revolving Tool-holder is a spring-loaded, ball bearing precision device which can apply variable force and cut or draw on uneven surfaces. It can be a drag knife, pen holder, plotter holder, and more!

To build this, you need to find a rod which can fit into your spindle collet(mine was 1/4" so I found a 1/4" rod). Then you need a spring which fits around the rod and is of the length and tension which supports your needs and z-axis travel. Finally you need some material for the block which can be drilled and hold it's shape well(I'd prefer aluminium but all I had was plexiglass). Then you drill 2 holes. One is straight through and the other is at 35 degrees. Put the rod through the hole and then hold it in place using c-clips and the spring. then tap another hole perpendicular to the hole at 35deg and insert a set screw to hold your tool.

I was able to use parts from a printer I tore down. I found a plastic collar with a bearing in it that fit the rod perfectly and a plastic washer to keep the spring from snagging the rotating collar. I used my drill press to hold the precision rods while I used a hacksaw to cut the c-clip slots. It has minimal play and a large travel with highly variable force. There's a tiny amount of play in the plastic collar but it won't affect the outcomes significantly.