"Projects" at georgesbasement.com
Marriage of Childs 0000 horizontal milling machine and a Unimat vertical milling head
Here's the combination as I made it around 1980.  I built the Unimat's downfeed mechanism and housing from scratch.
Downfeed is either with the handlever alone or by worm drive of the handlever through the small handwheel in front. Selection is made with the plunger on the left side by pushing both the plunger and the handlever pinion towards each other while rotating the feed lever.
Childs 000 HMM with a Unimat vertical head
Left side view of the Unimat installation
Drive view of the Unimat installation

   The Childs & Co. knee and table are quite robust, with ball bearings and tapered gibs.  The feeds operate very stiffly, however.
   The drive for the Childs 0000 horizontal spindle is by dual V belt drive from underneath.  Just one speed; choose cutter diameter accordingly !
   The CEKA Type U90 motor used to drive the Unimat vertical head is still available.
Childs 0000 knee and table
Childs HMM manufacturer's mark
Unimat motor manufacturer's nameplate

   The original Unimat CEKA Type U90 drive motor still works OK, even after 30+ years of little use.