The gun was just calibrated its brand new topcon. And my party chief turns the sets just fine I have to fine tune me I guess im not doing something or doing something wrong . I have the chance to one day be a party chief. I work for a small company that brought me on as the start of there expansion. This way they can train me there way from scratch.i have to be doing something wrong.
> The gun was just calibrated its brand new topcon. And my party chief turns the sets just fine I have to fine tune me I guess im not doing something or doing something wrong . I have the chance to one day be a party chief. I work for a small company that brought me on as the start of there expansion. This way they can train me there way from scratch.i have to be doing something wrong.
Don't kick yourself too hard partner. You sound like me 10 years ago when I got hit up to go work for a engineering/surveying firm. I had zero experience and that's why they wanted me - "so I don't have to break you of any bad habits". Surveying habits that is. 🙂
I was thrown on the gun in a few months without a clue what I was doing. It was a DOT job we were doing. All our traverse/control points had to be doubled in (set collect). I couldn't get them within tolerance (10" was our margin) for the life of me. I gave up several times. Our survey manager was determined to make me an I-man out of regardless everyone else was FAR more experienced. After about a week I finally nailed one almost dead-nuts on a set. Don't know what it was specifically but I was off and running after that.
Now I have been doing this 6 months and have seen several different methods of leveling a gun so far what procured do you follow for leveling the gun
Use tripods not poles/bipods. Check/adjust tribrachs often. Check that the prism targets are correctly aligned.
> Now I have been doing this 6 months and have seen several different methods of leveling a gun so far what procured do you follow for leveling the gun
Really? You're asking me? Golly mercy. I should be impressed that you asked me plus embarrassed that I can't answer. I think it would be one of those "I'd have to show you" moments. I was taught one way and got it. Then a party chief, Tony, I hadn't worked with before show me "his" way. And, somewhere in between I found my own way. I can't explain it really. I imagine others here might say the same thing.
Last time I got called up to help a few years ago, I honest to God couldn't remember how to setup. My PC, Wanda (yes, a chick), had to help me out. She had her way to setup but it was close to my old way I remembered and we were good from there.. until the rain put us out that day.
If one of my buddies were to call right now and need some help, I'd go, but I might be better on the rod or backsight than on the gun. My eyes are still good so I could probably turn good angles just fine.
What sort of backsight are you using? A deadman? Prism on a tribrach on a tripod?
Never much cared for the deadman because only me as the gunner would know where to site it. Tribrach: have you checked its level? How about your rods?
I would check/adjust our rods every few days. It only took me a few minutes. Some say two weeks is ok. Tribrach check was bit more complicated. That took about 30 minutes and requires a "dounut level".
> Now I have been doing this 6 months and have seen several different methods of leveling a gun so far what procured do you follow for leveling the gun
Well, I'll take a crack at this. FULL DISCLOSURE: I'm a newbie...probably more a newbie than you. I learned from this site (Bill93, Paul in PA, I can't remember), and trial and error:
1. Align the instrument face (the readout)in line with two of the three thumb screws.
Level: (Left thumb movement moves the bubble in the direction you want to go). That is, left thumbwheel rotates ccw moves bubble to right. ALWAYS move the pair of thumbwheels counter to each other, together. That is, if left is going ccw, right goes cw.
2. Turn instrument to right 60 degrees. Repeat #1.
3. Turn instrument to right 60 degrees. Repeat #1.
4. Go around the circle at least two times, using smaller and smaller movements of the wheels until perfectly level.
5. Re-check plummet for centering errors.Move instrument on tripod plate gently if needed.
6. Repeat steps 1-5 as many times as necessary to get perfectly level and centered (shouldn't take more than two cycles).
I kinda fighred as much . I have my own way two. And as for backsight ... tribrac I feel like I miss spelled that dont know when or if it has been cal. I do know the rod is checked all the time and its always nuts. What is a deadman. I want to be better and get there faster lol
Oops. 120 degrees, not 60. (You could do 60. But then you'd be working the screws on the far side of the instrument.)
Leveling a gun
I taught surveying for many years and had the opportunity to refine and practice this technique. These are the main points, and I probably left a few of the finer points out, but here goes:
If the instrument has a tribrach bubble, an instrument level vial and a three-screw leveling system with optical plummet, here is one way:
Mount instrument on tripod, never letting go of the instrument until it is secure.
Hold tripod by two closest legs and place opposite third leg on the other side of the setup point.
Look through optical plummet (or observe laser plummet dot) and place target on point on ground and then set the two legs being held. Keep instrument near level while performing this operation. With practice, you will get pretty good at this step.
Secure legs in ground. At this point, use the instrument leveling screws to point at the ground target when looking through the optical plummet.
By using the tribrach bullet bubble, work with the adjustable leg tripod by holding on to one of the upper leg parts, loosening the clamp, and sliding the leg up or down to center the bubble as near as possible. Watch how you hold onto the leg part and do not let the tripod suddenly collapse. This is easier shown how to do than explaining it! When performing this step, always stop raising or lowering the leg when the bubble is opposite one of the legs. Then move to that leg to raise or lower until the bubble is near center. Check optical plummet and re-point to ground target if necessary. Stop leg adjustments when the bubble is near center and instrument is still pointing to ground target.
Move on to the next phase of leveling by turning instrument so that the tube level bubble vial is along the same axis as two of the leveling screws. This step aligns the axis of the instrument with the three-screw leveling system.
Center the bubble by turning both screws simultaneously, but in opposite directions (thumbs toward each other or opposite).
Turn instrument 90 degrees and turn third leveling screw only to center the bubble.
Check optical plummet. If it is off center, loosen instrument mounting screw slightly and slide instrument along flat tripod head to re-center the instrument over point and snug instrument screw. Do not gorilla tighten - not necessary.
Start over with the leveling of the instrument with the tube bubble aligned with two screws and center the bubble.
Turn 90 degrees and level with the other screw.
Check optical plummet again. Repeat moving the instrument if necessary.
Fine tune the instrument leveling by rotating the instrument to align with two screws, leveling, and then rotating 180 degrees and check level. If there is any leveling error, then remove half of that error by adjusting the leveling screws. The goal is to split any difference so that the bubble is out by the same amount on both sides, or 180 degrees apart.
Rotate the instrument 90 degrees over the one screw, level, then rotate 180 degrees and check level. Adjust out half the error, if any.
Check optical plummet. If off the point, loosen screw, slide instrument, snug, and repeat whole leveling process using the tube bubble.
When I first started to write this, I realized what BigE said....it is easier to show you than explain it in writing. There are a lot of steps to perform, and things to watch when setting up over a point and leveling an instrument. I hope that I have given you sometching you can use. Some of the steps will be different depending on what kind of instrument you have. I am using a Leica with a laser plummet and an electronic plate bubble, so my leveling setup is much easier and faster, but the adjustable leg part is the same. I set up a tripod two or more times for each survey I do, and sometimes as many as over a dozen times a day. This just takes practice to get any good at doing. I can set my instrument up in about a minute. I have seen newbies take 30 minutes or more. It is a skill only learned by observing knowledgeable and practiced instrument persons and then practicing yourself with them watching and offering suggestions and instruction.
Try setting up an old K & E transit with a plumb bob and stiff-leg tripod sometimes. I can still do it, and even "throw a chain"! B-)
Leveling a gun
That's the way it should be done.
One thing that may or may not have been mentioned amongst all the good advice, is to relieve the tension in your tripod legs after you have adjusted them and tightened them down. This probably applies to the traditional screw clamp type, more so than the lever cam type.
Just to follow up, I'll try to explain. When you are done raising or lowering the legs, and have tightened the thumb screw; use your thumb and forefinger to gently apply pressure to the clamp area in an inward and outward direction. If you hear a small "creak" sound, there was tension or binding between the two wooden surfaces. You will then need to tighten the thumb screw a bit more. If this "creak" occurs in the middle of a set of angles, you will have difficulty obtaining tight splits.
Leveling a gun
> Mount instrument on tripod, never letting go of the instrument until it is secure.
> Hold tripod by two closest legs and place opposite third leg on the other side of the setup point.
> Look through optical plummet (or observe laser plummet dot) and place target on point on ground and then set the two legs being held. Keep instrument near level while performing this operation. With practice, you will get pretty good at this step.
> Secure legs in ground.
That seems to be the way most instrument operators set the gun up. I don't like the steps quoted above. If the gun is attached to the tripod when you set the feet, it puts stress on the tribrach and probably other parts. Especially if the tip of the foot is on a rock or root and slips or jerks. The tripod feet should be solidly set and the legs adjusted fairly close to where they will end up BEFORE the gun comes out of the box. I find very few people that can/will do as I suggest. I can accurately set the gun up faster than most. Of course, I may have an unfair advantage since I learned when I was 13 with an old Lietz transit on a fixed leg tripod with a plumb bob. No tribrach, no adjustable legs and no optical plummet.
Leveling a gun
Mounting the instrument after setting the legs would be a better practice. I cringe when my leg point suddenly glances off off a hidden rock and gives the instrument a pretty good bump. Not good! :-O Fortunately, this does not happen too often in Mississippi dirt.
I do use this practice when setting up on asphalt and need to tap the leg points a little into the asphalt with a hammer before mounting the instrument.
Leveling a gun
Here's how I was taught:
Secure the legs first. Nothing on the tripod. Nothing at all. (Sometimes, sand bags, rocks are needed to keep the legs steady, can't pile them up with an instrument already mounted.)
-Look at the horizon, make sure the tripod head is aligned with the horizon.
-Drop off a pebble or simply look down from the center of the tripod to the point.
- If all looks good, then put instrument on tripod.
- Secure the instrument. Close the case.
- By using the three wheels of the tribrach, place optical cross hair or laser beam on the point.
- Choose two legs (not 3, 2) to level the instrument.
- Unscrew the tripod' and slide gently the instrument over the point. Re-tight the screw.
- Make sure that the tribrach sits 100% over the tripod' head (No overhang)
- Fine tune the leveling.
We are using durable yet fragile instrumentation. To me, having the instrument or a simple tribrach on the tripod before having the legs secured is a big no-no.
Leveling a gun
> To me, having the instrument or a simple tribrach on the tripod before having the legs secured is a big no-no.
Is the tribrach without the instrument really an issue? I have been doing it that way for since I had I got my first total station and have never had any problems. Now, once the instrument is in the tribrach, that is another story...
Ken
Leveling a gun
Harold's advice is good. I want to re-emphasize some points.
I found this one very counter-intuitive until I analyzed it carefully. At the start you use the "leveling" screws to point at the ground point rather than using them for leveling, and change the length of the legs to level the tribrach (I kept wanting to change the legs to get over the point). Only after you are close do you use the tribrach screws for final leveling. When you change the length of the legs, you are approximately rotating everything around the ground point as a center, so the pointing doesn't change much.
Also, understand what your level bubbles are telling you. If you can rotate the instrument to any position and the bubble on the instrument always comes back to the same position (whatever position), then your instrument is level. If the bubble isn't centered then, it is the bubble that is out of adjustment. That's an easy adjustment to make.
The bubble on the tribrach is for coarse alignment only. Get the instrument leveled and then check if the tribrach agrees. If not, adjust the tribrach.
Leveling a gun
I have seen young workforce leave tribrachs on tripods in the back of pick-up truck, bouncing around. "It's just a tribrach" was the answer when we talked about this method of transport.
Certainly, in the hands of someone who cares for the equipment, the issue is less.
Adjusting out the tension in the tripod legs is also a good practice. I have noticed that when setting up the tripod, and I loosen a leg clamp, I hear and feel a "crack" and get a "shift" in the tripod position, causing another leg adjustment. When this happens, I just loosen and tighten all three legs or grab two legs and give the tripod a good "wiggle" and then continue my setup.
There is some really good advice in this thread. I want to add that an out-of-adjustment prism pole bubble will produce both an angular error and a distance error. These bubbles need to be checked and adjusted often as suggested above. Good advice.
SOH CAH TOA
I'm so old that I used Rowan and Martin's Laugh-In "Sock it to me" catchphrase as a memory aid for SOHCAHTOA when I first started out.
