Construction Tripod Adapter

JohnMiller3 · Jul 24, 2002

...I assume the eyepiece canot be rotated 180 degrees vertical ...

Hi Egon,

You're correct... it's not a transit... I think the scale is there because everyone else has it... strictly for a "rough reference"... but certainly not for any precision... /w3tcompact/icons/blush.gif

The Egyptians had no problems building the pyramids with knotted rope using the 3-4-5 method for right angles and water troughs for leveling... can you imagine what they could have built with our modern instruments of today... /w3tcompact/icons/smile.gif

Egon · Jul 24, 2002

John:
The Egyptian methods still meet my requirements and have been used more than once or twice.
Several weeks ago I was reworking our road into the lake. It lies at 90 degrees to the bottom of a hill of average 10 degree slope and also has a longitudanal slope to it. Having forgotten my hand level I reverted to using a clear glass mug with pronounced rings on it for determining if I was getting the road level. Water in the mug was hard to see so I resorted to filling it with an amber liquid from the camper fridge. Unfortunetly it was very difficult to get the level to coincide with the rings so frequent refilling of the mug was required. As it was hot out this was not much off a drawback. The method worked perfectly as I could stand back, hold up the mug and see how level the road was.
When squaring up building foundations I always use the 3-4-5 to start and use the diagonal measurements to finish off.

The self leveling level/transit combination can show incorrect angles if it is not level. In that what I am saying is the level could be set up so it will self level in a small arc but as the arc increases the self leveling feature does not have the range to compensate.
Egon

JohnMiller3 · Jul 24, 2002

...resorted to filling it with an amber liquid from the camper fridge. Unfortunetly it was very difficult to get the level to coincide with the rings so frequent refilling of the mug was required...
/w3tcompact/icons/grin.gif

Egon,

Now, I fully understand why they only use an "alcohol based distilled spirit" in levels... /w3tcompact/icons/laugh.gif

...The self leveling level/transit combination can show incorrect angles if it is not level...

There... that's the principle/purpose of "Doubling an Angle".../w3tcompact/icons/wink.gif

Spencer · Jul 24, 2002

<blockquote>In reply to:<hr>

Curious how you determined the previous level you were using was out by a degree or so when turning angles as I assume the eyepiece canot be rotated 180 degrees vertical and the ensuing two angles be compared.

<hr></blockquote>

I have attached a view of my property all plotted out on AutoCad by my surveyor. My property is the 9 sided lot in blue that looks kind of like the state of Nevada.

I was working in the corner that I have identified on the drawing. From that corner and going to the right (east) it is exactly 51.46 feet. I stretched a line from the two stakes put in by the surveyor and then measured 25 feet from the corner and set up my automatic level at that point.

I then lined the automatic level up exactly with the corner while the level was set at 270 degrees. I then turned the level to the 0/360 degree mark and centered a stake 100 feet out in the crosshairs. (It might have started at 0/360 and then turned to 270 I don't remember any more).

I then measured from the stake over to the property line and instead of it being 25 feet it was almost 27 feet. I did this same process three times and came up with the same results.

Then instead of starting with the level set to 270 degrees and turing to 0/360 degrees I started with the level a 0 degrees and turned to 90 degrees. The results were about 24 foot 8 inches.

Then I went from 90 degrees to 180 and so forth. So I went back inside and plotted it out on AutoCad (file attached in next post). I turns out that being 1 degree off at 100 feet is a difference of 1.81 feet. That is pretty much what I was coming up with on my own.

So I call CST/Berger and explained all this to them. After a couple of calls I finally got a call back from somebody quite high up. He explained that the auto levels are not meant for turning angles and an enclosed transit was what I needed. He was very helpful and I will continue to buy and recommend their products in the future.

Spencer · Jul 24, 2002

Here is the second file. I hope I have explained this well enough and not confused this issue any further.

Egon · Jul 25, 2002

Spencer:
As you now have the proper instrument my disertion on the level is only trivial information.
If you had set two stakes[ nails in the ground about 100 apart ] and the ran a string between them you could set the level anwhere on this line, use one stake as backsight and turn 180 degrees. This should put you right on the other stake. If there is an error the closer you set to one stake the divergence at the other stake should be increasing.
With a transit you verticaly rotate the eyepiece 180 degrees and check the angles. If the instrument is in alignment they will be the same. If not the divergence will be the exact amount only in the other direction. There are other ways too but this is pretty easy to do.
As for the attachment it may be so you can level the transit , center it over the turning point with a plumb bob, tighten it all down and then check for level again. It has to be level for 360 rotation. Optical plumb's are the easiest to work with.
As my experiences are all 30 or so years in the past and my memory never was very good I hope my information is correct and will be of assistance to you. {ie have trouble rembering proper terminolgy}
Egon

Spencer · Jul 25, 2002

Thanks for the tips

Spencer · Feb 6, 2003

I just referenced this post in another post so I thought I would give you all an update on the mystery adapter. As you know the transit attaches the tripods 5/8" - 11 threaded mount. The standard length threaded mount on both of my tripds is too long so you can't completely tighten this particular transit down to the tripod. The first couple of times I used the transit I had to place some large washers between the transit and the tripod to act as spacers so I could tighten it down all the way. Then around the third time I went to use the transit it came to me "hey, I bet that mystery adapter has a shorter threaded mount". Sure enough it has less threads on it so it allows the transit to be tightened down all the way. It fits perfectly in place of the original threaded mount on my CST tripod. I can't believe it took me that long to figure it out. /forums/images/graemlins/blush.gif

JATO_RaT · Feb 6, 2003

I have a Sokkia auto level and was wondering how you like the Stabila elevator tripod. So many times that would come in handy. I've seen them advertised in magazines. My levels are Stabila and they are my favorite. Rat...

Spencer · Feb 6, 2003

RaT, I think the Stabila elevator tripod is well worth the money. It works great with my rotating laser level because it is so easy to adjust the height. It is not the best choice transits or any other device that you need to center over a specific spot with a plumb bob or optical plummet. Most tripods like my CST tripod have quite a bit of travel in the center mount so you don't have to move the tripod itself in order to line it up over a specific spot. The Stabila, because of the elevator shaft, has no adjustment at all so you have to move the whole tripod.