From: muratlanne@gmail.com   
      
   "Jim Wilkins"  wrote in message news:v9njme$1eonm$1@dont-email.me...   
      
   There may be other ways to design a self-assembling gantry crane, perhaps   
   temporary or fold-out extra legs that make the end posts free standing until   
   the beam is bolted in place. Mine is set up such that I can lift the beam   
   and move the loaded trolley from outside the leg and beam areas.   
      
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   Here are some ideas that may not be too difficult to DIY. They appear to use   
   common structural shapes pinned or bolted together at flat plate fittings   
   small enough to make with hobby sized machine tools.   
   https://m.sevenindustry.com/portable-gantry-crane/aluminum-gantr   
   -crane/aluminum-portable-gantry-crane-a.html   
      
   For at-home use I would trade the compact folding and rapid setup for more   
   bolted triangulated bracing to reduce bending stress on the legs and joints   
   and increase load capacity. I built my tool shed tall enough for 8' stock   
   and stepladders standing upright. This defines the sizes of what I build to   
   store in it, like the gantry components. Uncut 8' studs give a wall 8' 3"   
   high and aluminum Z strips keep water out of the joints in the siding   
   panels, which are somewhat sheltered by the eaves.   
      
   A track made from two channels can be attached to uprights and diagonals by   
   sandwiching them between the channel webs. For instance a two channel track   
   could be attached atop wood posts with angle iron trimmed to fit between   
   them and bolted to the posts. The diagonal brace could also be two angles   
   with their ends cut down to fit between the channels and bent flat against   
   the post, though mine are 3/8"  bar welded into the slotted ends of pipe.   
   The outer post for my temporary track extension is a braced landscape timber   
   with the track hung on a 1-ton-rated turnbuckle to level it. I think a   
   gantry track made from channel iron makes sense if you need manageable   
   weight, compact storage and versatility for one-time setups more than high   
   capacity for frequent use.   
   jsw   
      
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