You could go really machinist crazy and cut threads on the posts supporting the rack, with thread follower blocks on the rack. Then gear and worm at the top to drive the screws from the crank. Rod and second worm, or chain and sprockets to synchronize the screws.
I had a router table that was set up this way to raise and lower the heavy vertical table on which the router was mounted. It worked very well - nice and smooth.
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Stupidity got us into this mess. Why can't it get us out?
- Will Rogers
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