OP,
Look into dealers that have a used inventory....That said, for an EDM with all the additional equipment you will need the price tag can easily go over $3,000. You definitely want something that is calibrated to start with.
As you obviously know, you are allowed to do your own layout as long as you are doing it for yourself and not offering it as a service alone. I do recommend being very selective in the mountains laying out houses.....as there is a big difference between a house on the flat as opposed to a hillside house with 30-40' high foundations with step downs.
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My word of caution....When I was working in your mountains, I ran across 7 properties where the house was over the existing boundary lines and all 7 were laid out by contractors...not surveyors. Dealing with odd lot shapes and the vertical changes make things interesting to say the least. If you are laying out houses in the flat mainly, then it would be a good investment and make sure to double and triple check everything.
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I have a Topcon GTS 235W that I bought brand new and have never used. I??d consider selling it and can send you pictures and more details tonight when I get home from work if you??re interested.?ÿ
We have all seen the mistakes associated with inexperienced people doing things they don't know how to do and it is not limited to surveying by no means.
Several situations stick in my mind. One of which was a homeowner deciding to to do his own poured concrete foundation walls and he did not turn the rebar at the corners to extend into the next wall. When he back filled it the walls collapsed.
I still would like to hear how this fella plans to layout the houses.
He wants to learn how to do it and save money and I cannot fault him for that but I am still curious to hear how he thinks it is gonna work.
A total station is a tool and I cannot count the number of people who think that it (the total station) majically tells me where to go. They cannot grasp that it just sits there on the tripod until I tell it what to do.
All too often, the general public sees us come out set up equipment, turn angles, measure distances, and set stakes, go home in 3 or 4 hrs, while they work a whole 10 hrs.
We charged $900!
They, thinking of cost per hr, come up with 300 bucks an hr, and decide to "eleminate the waste". Much like cost per lb of nails.
They never see me up up till 11:00 the night before, getting all the coords right. Figuring out how to tie into ground control etc.
And checking pole bubbles, adjusting tribrachs, analyzing why a distance is wrong, because it was a 30mm offset prism, BUT in fact, field practice, it's a 33mm offset prism, and the other prism is 29mm offset. Cause we bought em off ebay...
Or, the plummet got bumped on the last job, but the "new guy" didnt tell us, cause he at least wanted to make his 1st paycheck.
When you buy new survey equipment, it always has to be checked and adjusted.
When you buy used, it ALWAYS has to be checked, especially that nothing is loose, or sold in the middle of adjusting.
I could go on, but Kent Mc is not here, and somebody has to change this diaper.
Quite simply, there is no such thing as "simple surveying".
All measurements contain error, and it must be quantified, if we are not gonna get our bohonkus handed to us.
To quote a good surveyor, talking about a bad surveyor:
"The biggest favor you could do him, is to kick his tripod and instrument, and knock it over on concrete."
If you want a piece of the measurement pie, keep a calibrated 100' tape handy.
And, know at what temperature it's actually 100' long.
Some jobs, that does not matter. But, know when it does.
In short, if you want to ride my horse, you'd better learn his ways.
Nate
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Frozennorth thanks for backing me up a little. Feeling a little attacked all of a sudden. Seems like everyone wants to prove how smart they are and how I can't possible take on learning how to use a total station for foundation layout. I feel like every one is assuming I'll just buy a tool and it will do all the work for me. I know I need knowledge and I have already investigated courses in my area so I can learn to use the tool once I get it. I just wanted some advice on buying used units.
Go for it. It is not rocket science.
First order of business, learn how to check the adjustments, and then learn how to adjust it yourself.. that too is not rocket science.
There are Lots of surveyors that are living hand to mouth, even in these super fat times. Not because they are not great surveyors, but because they are not good at business. Find one. Offer to buy his equipment, with a little training thrown in.
Some good advice above as well as some warnings. Most of that comes from "our" experience in working on sites or working on sites after others have done some layout and we had to fix things.?ÿ Take it to heart I guess.?ÿ My recommendations would be to buy an instrument that's about 5 years old and from a dealer in survey supplies.?ÿ Have it calibrated and adjusted in case it hasn't been already.?ÿ Then I think it might be best to hire a local surveyor on your next project and then duplicate their layout to see how close you would get to it.?ÿ Most important is to learn how the instrument works and how to check yourself and make sure your not getting some odd results.?ÿ Probably a quarter of a job is to do those checks on construction sites.?ÿ
I will pass along one of my favorite construction stories.?ÿ I was survey PM on a mid rise building here in the city and the contractor had purchased his whole setup brand new to do their own layout.?ÿ Happens a lot so no big deal from me.?ÿ I get a call one day:?ÿ "...your control is all f$@#ed up.?ÿ You need to get your crew out here right away!!!?ÿ How the hell could this happen!!"?ÿ I am very familiar with the crews checks on the project and the chief on the job is one of the best around on construction.?ÿ My response to my client:?ÿ " We will be out there right away."?ÿ Crew goes to the site and checks the control with our gear....nothing wrong.?ÿ Everything checks on all directions.?ÿ Our chief asked the Supt to have their guy setup on the control so he can help them with some checks.?ÿ Looking at the prism pole it was clearly out of plumb by tenths of a foot and their source of error.?ÿ Contractor learned something that day and we got paid for time dealing with their unknowns.?ÿ
I am certain most of the people posting above have similar stories.?ÿ Most important lesson is to know and understand what you don't know.?ÿ Some of us it took years of daily work on sites to do a halfway decent job of putting things in the right place and to know where and when to spend extra time on.?ÿ When you're not sure, hire someone to help.?ÿ Even keep them on a site for an extra couple of hour to help show you a few things.
Good luck,
Dan
Here's a piece of advice, judgement free: most manufacturers' EDMs are calibrated to use tripod prisms with either a 0 mm or a -30 mm offset. Leica is calibrated to use a -34.4 mm offset, but they call it 0 mm. It's a real pain in the ass to be sure of using the correct prism offset when non-Leica prisms are used with Leica total stations. The upside is that Leica makes some of the most reliable equipment.
20+ years ago I was in your position , not as a GC , but as a concrete contractor . I couldn't afford to hire a full time layout person, so I decided to do it myself. I went to the local Sokkia dealer where I rented a Set 500 with a prism , pole and a mini prism, both with -30mm offsets. After creating a mockup job ( 4 points in a rectangular pattern and 2 offset points as "surveyor " points ) I went to a local park with my business partner and I tried to lay it out.?ÿ My first problem was that that the instrument was by default?ÿ set to read Sloped distances, so when I checked by tape, it didn't quite work. A phone call to Sokkia and the problem was solved by changing to horizontal distances.?ÿ
My procedure was as?ÿ to set up on a Surveyor point, sight the oposite surveyor point, set horizontal angle to 0, go to coordinates and read?ÿ the prism. By setting the Hz angle to 0 you tell the instrument that the point you are set up on is of coordinates (0,0) meaning Northing 0, Easting 0 and that your north direction is defined by the 2 surveyor points. You can layout any points that are on lines parallel or perpendicular to the line defined by the 2 surveyor points. You have to calculate the coordinates of the points you want to layout and by taking a reading of the prism , you'll know how far you are in the north and east direction from the given point.?ÿ
