From: muratlanne@gmail.com   
      
   "Jim Wilkins"  wrote in message news:voa9s4$lg7q$1@dont-email.me...   
      
   "Richard Smith"  wrote in message news:m1y0yfr11p.fsf@void.com...   
   One is, given saw cutting long lengths of "box" is accurate transversely   
   but less so "vertically" due to spring in section and distance outrigger   
   is from saw, position "flash" at "side" as sawn so have "square" end   
   as do "measure along" direction AND drill can go through both sides of   
   "box" on drill-press, not risking hitting "flash" on opposite side.   
   ------------------------------   
      
   The base on my 4x6 horizontal bandsaw can twist from floor/pavement   
   unevenness and make the blade cut unsquare vertically. I fix it by checking   
   blade rise and fall with a square clamped upright while moving the base feet   
   around until the blade descends adequately parallel to the square for the   
   job, whether cutting for machine parts or firewood.   
      
   The general solution for permanently installed machine tools is to level the   
   machines' working surfaces, the level and plumb bob being inexpensive   
   instruments that very accurately indicate direction.   
      
   An expensive one:   
   https://en.wikipedia.org/wiki/Gyrocompass   
      
   Recent microelectronic devices can sense the direction of gravity in your   
   cell phone or a Segway.   
      
   My South Bend lathe has an alternate method that works on a ship. The   
   tailstock end of the bed is on a lengthwise pivot and restrained by   
   setscrews. Loosening them lets the ways untwist, then the screws can be   
   gently run in to contact.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)