On flat ground with three people...
A holds zero and 140' on a point.
B holds 30' on a point, loops the tape around and holds 40' on the same point.
C holds 80' on a point at right angles to line A-B then loops the tape around and holds 90' on the same point. Line C-A is the hypotenuse of the triangle.
Everyone stretches the tape tight and voila A-B-C is a right angle with no fancy instruments or calculations required.
See Plane Surveying, Tracy, 1906.
Um, could I get a worksheet?
Thanks!
🙂
N
Assuming 10-ft loops to avoid kinking the tape, why not use the whole tape?
A holds 0 and 200
B holds 45 and 55
C holds 115 and 125
AB = 45
BC = 60
CA = 75
ratio 3:4:5
AKA the 3-4-5 method....
for quick and dirty- a folding 6 foot rule will do the same. 3 segments, 4 segments, and 5 segments.
I discovered that one day in the field.
I thought to myself, why did I not think of this before?!:-/
Watched my friend in Chicago that rents tents (big ones for big events) do that.
> On flat ground with three people...
The bigger question is: Where are you going to find a 3-man crew these days?
Get two rag tapes and some 60s.
Hold the hook end of one rag tape with a 60 at A. Measure out 30' to B. Hold the hook end of the second rag tape with a 60 at B. Pull the two tapes so they intersect at 50' from A and 40' from B to set C (or use whatever multiples of 3-4-5 you like).
Voila only one person required :-).
Laid out a lot of foundations using this technique back in my hammer swingin' days.
I laid out my 30x40 barn with a tape. No different than the cross ties on construction jobs.
After we got the pad built and the points laid out, we pulled 3' o/s to the point, dug the hole, set the post in concrete and got it back within 0.02'
As we built the barn, it was apparent, that in setting the points, one had "drifted" 0.08' and it was found when we set the R panel.
It was still good enough for a barn and I didn't care that it was 1" out of square.
Without laying out the barn with a tape twenty times to establish a realistic estimate of your standard error, then running the results through Star*Net, how do you really know how close you got it?
Best Regards
> Without laying out the barn with a tape twenty times to establish a realistic estimate of your standard error, then running the results through Star*Net, how do you really know how close you got it?
>
> Best Regards
I view all of my measurements as error free and absolute so......
Best Regards
🙂
