I didn't understand it.
On Tue, 20 Oct 2009, Tom Hodges wrote: > That's a little difficult to use if you're visually impaired. > > > > From: [email protected] [mailto:[email protected]] > On Behalf Of Ron Yearns > Sent: Tuesday, October 20, 2009 12:00 PM > To: [email protected] > Subject: Re: [BlindHandyMan] Non-euclidian geometry. > > > > > > One thing I used a number of years ago on laying out and framing for a > concrete foundation is a water level. It consists of a length of clear vinyl > tubing. Half inch in diameter works well but not real critical, just if too > small you tend to get some capillary action. Make sure it is long enough to > come up to where you are wanting to level off with the rest laying on the > ground. Almost fill it with water. Water seeks its own level so the two > water levels seen through the clear tube will be level with each other. by > holding it near stakes or walls you can put level marks to measure down from > or to use if they are the right height.. This probably isn't as accurate as > one of those laser level but for long lengths I think it does real well. > Ron > > ----- Original Message ----- > From: Dan Rossi > To: Blind Handyman List > Sent: Tuesday, October 20, 2009 9:09 AM > Subject: [BlindHandyMan] Non-euclidian geometry. > > I need to call in NASA to investigate my basement. Apparently, my > basement is a very special place where Euclidian geometry goes right out > the window. > > I have two parallel beams that are nice and level. The level beeps > continuously as I move it along the beams. I lay a 2X4 across the two > beams and that 2X4 shows level. So, if the two beams are level, and they > are level to each other, then a 2X4 placed across them at any point will > be level. > > Here is where it gets interesting. At one end, the 2X4 is level and all > is happy. At the far end, if I level the 2X4 it is well above the one > beam. And I don't mean like a quarter of an inch, I mean like an inch and > a quarter or a bit more. > > This is actually impossible. But that is why my basement must be > declared a non-euclidian zone. > > I think it has to do with the fact that even if the level is off a tiny > bit, like 0.1 of a degree, over 15 feet, that is actually 5/16 of an inch. > Do that three times and you get nearly an inch. Plus the middle beam that > I was trying to level wasn't fully supported yet, so is bending and > flexing, and so was the 2X4 I was using. Add all that up and you get a > lot of error creep. > > I need an 8 foot level, but not sure I can get that one passed SWMBO. I > might try using my saw guide on edge which should be pretty stiff. > > -- > Blue skies. > Dan Rossi > Carnegie Mellon University. > E-Mail: [email protected] <mailto:dr25%40andrew.cmu.edu> > Tel: (412) 268-9081 > > [Non-text portions of this message have been removed] > > > > > > [Non-text portions of this message have been removed] > >
