Re: adjustable square for SHS / box sections

"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.
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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.