From: null@void.com   
      
   "Jim Wilkins"  writes:   
      
   > "Richard Smith"  wrote in message news:m1a5d7bsh1.fsf@void.com...   
   >   
   > I have contributed - this has started to happen.  I used "the bubble"   
   > (spirit-level) on some fabrications, and found that what it cost in time   
   > to set things off parallel at the first stage was more than made-up for   
   > by the "ideal" time it took to fit-up and weld the rest.   
   > Show the approach and the corrections, the owner and designer where on   
   > the press-brake with dial-gauges, etc., and made adjustments.   
   > ie. there is something positive going on. ...   
   > -------------------------   
   > Could you expand on that?   
   >   
   > I found out the hard way how much welds can distort a precise   
   > alignment, especially a weld across an inside corner. I had to jack   
   > the sawmill ladder frame parallel (enough) and mill the shrunken gap   
   > in a bending brake hinge assembled from surface-ground plates. The   
   > surface welds along the sides of the plate stack didn't destroy the   
   > 0.005" fork/tongue clearance, but welding inside the fork did.   
   >   
   > Do diagonal or fish mouth/tail ends (vs square) improve stress   
   > distribution and/or reduce distortion in butt joint splice plate   
   > welds? One end of the splice plate would be bolted, the other welded   
   > after aligning the beams.   
   >   
   > When I was building custom machinery the press brake operator and   
   > welder compensated for distortion, the all-welded machine frames were   
   > square to 1/32". They were mostly multiple 19" relay racks that we had   
   > to fit the equipment panels into, so we would see any error. I knew   
   > they marked the prints with allowances for bending and welding but   
   > they didn't share, and the front surface welds had been ground and   
   > filled as invisible as auto body repairs.   
   > tia, jsw   
      
   You are well ahead of me.  i doubt i can help.   
      
   Press-brake - they have a press-brake, yes - good.   
   Not new when bought.  Is small "fabco.".   
   Seeing if corrections / calibrations needed to go in to the settings, I think.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)