Retractable internal screw cutting tool

[Toolmaker51]

excerpted

Hi All
The drawings have been modified and updated for a third time today, as I keep coming up with improvements...sure there will be further ideas and improvements by you and myself. Is there such a thing as the perfect tool? The Home Engineer

Sure there is; just hasn't been built yet. There is a related quote; attributed to those who make gunstocks. "In this blank is an ideal rifle stock; you just need to remove the extra wood".
Easier said than done.

Since so few retracting holders have appeared over time, fact you are cutting materials is already significant progress. Hooyah for thehomeengineer!