Teaching machine design & mechanics by jacques maurel

Screw cutting made easy  (home made Snap-tap attachment)This attachment is fully described in the september and the october 2013 issues of
"Engineering in miniature" magazine.

Photos of the genuine attachment:

Video of the home made attachment at work:

Close up of the cutting tool:

A near relative of this attachment named: "High speed thread striking attachment" is described in "Model Engineer" Issue 4177. Principle:

The problem is : what happens if the feeding force is greater than the spring one?