I was really unsure of where to start this thread, since it's kind of an add-on to my furnace-build, but it's also a machine at the same time .
After having read, re-read, thoroughly studied Gingery's design and considering caster's feedback of 'rail-binding', I'm thinking of modifying Gingery's design by substituting square-tube vertical rails for his two 45*-rotated angle-iron rails. To help further, I'd use four sliding-door rollers (with bearings) on each side of the carriage, connected to arms supporting/lifting the furnace body. This whole moving/lifting mechanism would all be one unit. I'm thinking of using a scissor-lift type mechanism to help affect the raising/lowering. Here's a super-duper rough drawing:
The diagonal-lines represent the lifting levers, they need not be top/bottom symmetrical, only left/right - i.e. I may make the bottom ones shorter/longer depending on leverage. As for actually moving the levers (and the 100+ lb of furnace body, lid, and carriage), I've researched two options (I'd love some opinions and/or other suggestions):
As I see it, Option-1 has both a cost advantage and a "manual override" in case air-pressure dies. The biggest disadvantage is likely lifting speed. Option-2 address the lifting speed (0.3-in/sec) issue, and mechanical simplicity (less to go wrong) but costs three-times as much and has no built-in manual override (though the quality is quite high - heavily ISO-certified product. Either would likely attach to the frame-bottom, and the center pivot (middle "X") of the scizzor levers.