I'm modifying an old pony trap to correct the balance (which is wildly off). The bench seat assembly is supported by a pair of horizontal and parallel lengths of steel tube, about 30 mm OD, but not really good enough to be bearings (although I could use a split polymer bearing, clamped in position, if necessary). I would like the seat to be adjustable fore and aft, rather like a car seat, to accept one or two drivers of different weights. So it probably has to move through 12 inches or so, rather more than a standard car seat (or I would just adapt the runners from one of these). I'm wondering about using domestic or wardrobe sliding door gear. But while I think about it, I'm trawling for smart ideas for off-the-shelf sliders. I need a low tech and relatively low cost solution, but can trade cash against time. Load capacity of runners needs to be 2 people, say 150 kg, but it doesn't have to move under this load. Could MIG weld door or car seat sliders on to the seat and the shafts as required.
TIA