Did someone say "crane?" About (OK.. exactly..) a year ago, I turned 60, and a few months before that, I had a mild heart attack. For my 60th, my wife offered a new computer system, but I suggested instead the materials to build my dream shop bench. 10 deep drawers, push-off height for my table saw and two embedded bench tools (drill press and band saw) that flip up for use, down into the bench for storage. Weighs b/w 600-800 lb, glides on locking casters, and makes my shop way more functional.
While bringing in the sheets of 3/4" fir plywood for the benchtop, still recovering from the heart attack, I was really feeling my age. Thinking how my clock is not rolling backwards, I started designing my "skyhook" system. From shuttling material to the saw, to moving heavier tools like the thickness planer or the MIG welder around, it would be a hoist/crane modelled on the full gantry type seen in large industrial shops: girder beam rolling on rails to span the entire shop, with a hoist and LED shop light in one assembly, rolling across the bottom of the beam. I can have lift and work light anywhere in the shop and anything lifted can be moved to any other point in the shop. Yes! Bring it on!
That idea came almost a year ago (61st birthday today!) and the bench is long done. The crane? I'm down to the last challenge and it will be done. That challenge: the power wiring. The large industrial systems use something called a "festoon" cable. Designed to loop when compressed, on both the long rail, and the cross beam, it's a key part of the beauty of the system. But trying to downsize that part, and do it with off-the-shelf components, is proving more difficult than I thought. I think I'm almost there, but who knows...
The long rails started as simple angle bolted high on the walls, the beam rolling on casters (2) on either end. The beam on custom steel brackets to accommodate the casters and keep the beam squared. Ha! The 12' span of the beam (not a huge shop..) meant "square" was a relative thing, not able to be strictly controlled by 4 casters rolling on steel angle. The beam would turn slightly and while not coming off the rails, would surely jam and not be up to the job. I extended the reach of the beam-end brackets, added turnbuckle stiffeners to limit bracket play, all with no appreciable improvement.
Finally, I realised that the simple track/caster idea would never work. I moved on to barn-door track, the same used on the cross-beam. Stable and smooth action and with two 4-wheel cars at each end, the twisting is self-corrected, or absorbed, without degrading lateral motion. It took a while to detail the new mounting system for the box-rail, but thankfully, it worked a charm and the entire system now rolls smoothly in all directions. The design capacity was for about 200 lb, while all components are rated for about 400 lbs. In fact, it will rarely be asked to exceed 100 lbs. Lots of extra room there...
Onto the power cabling. First idea was to use a soft-sheathed extension cord (SJTW 16/3) to be clipped to an I-beam curtain rod system about every 12" and enjoy the elegant hanging loops when the hoist-head or the beam was moved across its span. Uh, no. The cord just wants to twist as it gathers. Not at all conducive to my goal. Now, I am onto an SPT-3 (flat) 16/3 cable, and am just testing adding weights to the loop-bottoms to keep the cable playing nice as the hoist/light head and cross-beam move back and forth around the shop. So close...
Yeah... "crane".. Photos to come.
