M7 Moving Steps

[joe mendel]

The case of the moving steps is quarter-inch plywood with mahogany veneer on the inside and eighth-inch thick white oak siding and wenge trim.  The steps are spalted butternut and red cedar and they rest upon maple cams and the steps are joined together with teak dovetail supports.   The dark shadowy Billy B. is gaboon ebony.  The drive shaft is turned from curly prymiria and is attached to the bubinga drive gear with a wedged tenon.  I used manufactured dowel pins as the teeth of the offset gears.  I wound up having to alter the number of teeth from 13 to 15 teeth to get the gearing correct.  Much of this M7 project incorporated a number of "do-overs" because even though I had the concept in my head, sometimes my math did not equate to the actual behavior of the system.