I just watched a You Tube video about "bucking in" with a level instrument. Each time the guy adjusted the foot screws he "tapped" the instrument. I assume this was to be sure the compensator or pendulum wasn't stuck.?ÿ
I was thinking this is an old trick, but the video is from last year. The manual for my automatic level does not instruct me to tap it when setting it up. There are some old Wild automatic levels that have a button to swing the pendulum. I still think the technology has eliminated the need for that.
Here is a link to the video.
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Historic boundaries and conservation efforts.
Old habits die hard.?ÿ I hope it's the same for old surveyors!
Maybe he read Wolf & Ghilani somewhere along the way.?ÿ "...lightly tap the instrument, and after it vibrates, determine whether the same reading is obtained."
I turn a leveling screw near the front or back, first up and then down, to see if it returns to the same reading, and watch for a smooth settling in.?ÿ Much better test than tapping.
Tapping while watching the crosshairs is the only way to go on some levels (and a few T1 model 70's).
Hell, I still tap my digital level.?ÿ Old habits die hard (have not used manual automatic level in 25 years).
My wife would point out I'm a little OCD.
Yes, I poke the button on mine.?ÿ
Doesn't mean much if you don't peg it.
I still do it. Pretty sure that most digital levels still use a pendulum compensator, so if it doesn't hurt the instrument no big deal.
I did like the ones with the plunger button to "tap" it for you.
It has been a while and none of the differences matter but he takes some steps that I do not.
I do not tape up from the floor for my initial set up.
I do not check 90 on the level bubble on every set up, I usually check 180 for bullseye bubbles.
Unless the ground is slippery and I need to make divots for the feet I will keep the legs fixed for the most part and adjust the HI by moving the whole leg instead of adjusting the length of the legs.
I tap the level before I look though it, I do not think I would tap it after adjusting the footscrews a mm, but maybe I would, it is sort of a compulsion as Mr. Putnam pointed out.
Once I am in the range that the footscrews can travel I will let them take me there, I am not going to adjust the length of a leg by 0.002.
I will use whatever the bosses want but would skip the vinyl target altogether or use a smaller one just to avoid making a level line that much longer on the wall.?ÿ
If I waste six and a half minutes watching a youtube video I usually do not waste another by writing about is so, there all exceptions to most rules in these things.
I actually bucked in with a level last week to check a piledrivers level, it was the lowest level level I have ever used and was out a hands width over 100 foot. Some attempts at savings are really not worth is in either the long or the short run.
Once I am in the range that the footscrews can travel I will let them take me there, I am not going to adjust the length of a leg by 0.002.
Certainly.
I would also note the main purpose of resetting the legs for the check shot is when you are reading a rod, so as to get different small reading errors and also catch reading blunders. In the case of the video it serves no purpose and adds time. It would be just as effective to wiggle a footscrew and reset to the target.?ÿ
The most critical thing is to make sure the pendulum is moving freely in its working range, regardless of what shows on the bubble. The bubble is the thing most likely to be accidentally out of adjustment if you have pegged the instrument in recent memory.
I thought I was an anal-retentive perfectionist.?ÿ Apparently not.
We use a digital level, so I've never thought about tapping it to free the pendulum compensator, if one exists. I've never heard of the term bucking in being used in level work. We always called it setting up on an HI. I just found something interesting.
The Topcon DL Digital Auto Level is equipped with a shock-resistant pendulum compensator with a magnetic damping system that allows you to take a single measurement in only 2.5 seconds.
That's the same level that we use. I wonder what a magnetic damping system is. Bill?
I wonder what a magnetic damping system is.
Watch the whole short video for a full explanation, but the best demonstration is at this time:
You know what happens when you don't check the compensator on every setup? You get to do the whole setup over as well as any dependent setups that followed. I've been doing this stuff for nearly 40 years and I had the privilege of having to chase down my negligence this past week. We were using a modern auto level and I just forgot. I don't use a level enough that it's muscle memory anymore.?ÿ
Quick smack on the tripod legs after levelling, here.?ÿ I still tap on the digital level for whatever unknown reason, occasionally.
I'm more conscious of the slip,slide, or spring in the tripod setup, than a stuck compensator in a modern level.
Wild NA2 still in daily use - you have to put your hand to the instrument body to point onto the stave - just press the button and ....PEACE OF MIND... no time wasted.