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Custom surveying equipment
Posted by jimcox on August 10, 2017 at 8:16 pmWe had to locate 234 driven wooden piles for an as-built survey.
Height was not needed, just position. But still it was going to take quite some time to locate each centre, level the prism and measure.
So I knocked up a device to quickly and easily locate the pile centres.
It worked really well.
Yup – an inverted waste basket with an attached prism
(sorry about the poor photo – the autofocus on my cheap camera doesn’t like the wire mesh)
The piles turned out to be bigger than expected ( 300mm vs 250mm ) and it did not fit over them as planned, but it was easy to get the centre just sitting it on the cut ends.
So what’s the best qizmo you guys have made?
jhframe replied 6 years, 8 months ago 18 Members · 35 Replies- 35 Replies
I don’t have photos handy, but here are a few of the one-off gizmos I’ve produced:
A short (1 foot-ish) fixed-leg tripod for use with an SNLL121 laser plummet in tying out/tying in monuments in holes or wells. I’ve used this a lot on monument preservation projects.
Another short fixed-leg tripod (smaller footprint than the above) for supporting an antenna over a mark in the top of a 10-foot granite column. (I haven’t actually used this one yet.)
A couple of known-length bars that mount on a prism adapter, for use in precise tribrach height measurement when trig leveling across a river.
A pair of 10-foot PVC pipe handles that clamp onto a 25-foot fiberglass level rod with prism on top, allowing me to safely locate some valves that were in large (10′ diameter?) and deep (15′?) excavated holes with unstable edges.
A robust housing for a Bluetooth radio that securely attaches to my data collector.
I’m sure there are others, but those are the ones that immediately come to mind. Fabricating stuff like that is my idea of fun.
Richard Imrie, post: 441283, member: 11256 wrote: used the eyeometer
:gammon:
Brad Ott, post: 441289, member: 197 wrote: :gammon:
Yes, the two that I have, I have had for as long as I can remember. They are auto focusing and can be adjusted for parallax and so far have never needed to be calibrated (touch-wood).
I took a mag mount for a GPS antenna and attached an arm about 1.5′ long and placed the robot prism on the end. I could drive slowly and locate road (rural) centerlines accurately and not be over the center.
Freedom is just another word for nothing left to loseWe built a trailer hitch mounted GPS bracket once. We slipped the pole down into the bracket and used it for locating center lines of logging roads on a project. We mounted this on a side by side utv.
Richard Imrie, post: 441298, member: 11256 wrote: Yes, the two that I have, I have had for as long as I can remember. They are auto focusing and can be adjusted for parallax and so far have never needed to be calibrated (touch-wood).
My two auto-focus, parallax compensating, inertial stabilized, eye-o-meters are also data collector, range finder, and low order compass.
Old atv from years ago. Made a nice bracket of pvc, well triangulated…..that was before I learned to weld. Only picture I had was it stuck of course.
Early 90s, Trimble 4000SL days, long corridor topo project. Mounted the giant pizza pan L1 antenna to handle that straddles a total station. Given the 1-2 hr+ observation time back then, the crew ran topo with the antenna on top while collecting gps data. We had to do topo and gps control simultaneously.
A robust housing for a Bluetooth radio that securely attaches to my data collector.
I’m sure there are others, but those are the ones that immediately come to mind. Fabricating stuff like that is my idea of fun.
Jim Frame
(How do I reference a post?) I saw Jim Frame’s housing – really professional looking device. Makes me kick myself for not taking shop in high school.
jim.cox, post: 441255, member: 93 wrote: We had to locate 234 driven wooden piles for an as-built survey.
Height was not needed, just position. But still it was going to take quite some time to locate each centre, level the prism and measure.
So I knocked up a device to quickly and easily locate the pile centres.
It worked really well.
Yup – an inverted waste basket with an attached prism
(sorry about the poor photo – the autofocus on my cheap camera doesn’t like the wire mesh)
The piles turned out to be bigger than expected ( 300mm vs 250mm ) and it did not fit over them as planned, but it was easy to get the centre just sitting it on the cut ends.
So what’s the best qizmo you guys have made?
I use the same type of basket for percolation tests for septic design.
Soft bottom soundings using a 12′ skiff with a small outboard. There was a brisk cross wind so it was not possible to hold the rod plumb from the boat.
Went shopping, got some 1″ PVC pipe and fittings, we made a T base for a free standing fixed hight prism rod.
After being forced to improvise and use a grappling hook a float on a recovery line was added.Raw sewer setting pond study at Lemoore Naval Air Station, California… several ponds.
The shores were lined with condoms.Hazmat suits. Me, my ace assistant (woman), and a biologist/ health scientist type (woman).
Ann and I traded off instrument and boat duty, the scientist stayed in the boat taking samples.
Nobody got sick.that was in the mid 90s
During the Ford expansion in Louisville, circa 1987, they were going to build vertically on the existing structural steel to expand their plant. We had to not only locate the structures as an as-built, but had to determine if any of the columns were out of plumb. With all the operations and equipment of an operational facility, it was not necessarily feasible to drop plumb bobs and measure any differentials.
So, the Pocket Surveyor was invented. We took a 3″ diameter reflector like you would find on a bicycle (or roadway post) and mounted a threaded nut on the backside. From that, you could insert a 6″ piece of all-thread into the rear of the unit after you climbed the column. Once the column had been vertically accessed, you would insert the all thread rod and then shoot in by the EDM in use at the time (Beetle, if I recall), the upper and lower elements of the column.
From that, you could determine, with reasonable accuracy, if any of the columns were out of plumb.
The key was, we had to measure a bunch of known points to establish baselines prior to using the Pocket Surveyor. From that, we had to determine the offset for the prism… seems like the offset went from -40 millimeters to +1200 or thereabouts. But, the item worked as we thought it might.
This thread prompted me to dig in the store – quite a collection so I’ll make several posts.
We had a viaduct to survey for new bearer pads. The client wanted the exact positions and levels of each beam, both ends. Several sizes of beam and the height from ground varied between 2 and 7 metres high. About a dozen beams on each span and 15 spans.
This little device, with lots of extension rods on the bottom, enables the prism to be held a given distance from the cross beam face. The prongs are adjusted to suit the width of the beam to be measured and then it self centres. The cross bar is a known height above the prism. We could get scaffold access because there were roads and a railroad under most of the spans.
Another thing held in the air. We needed to monitor a number of houses with (rapidly) ongoing settlement, so exactly the same point was needed eqch time. This little device sits round the house corners, held at damp proof course at low level and the top butts up under the eaves board at high level. Again, used with extension rods to get the height. The targets are a fixed distance from the centre and top/bottom so a single instrument set-up can observe a number of houses.
Things to get where you cannot reach – these were used on various mechanical plant to get levels.
The yellow device has two scales reading from the base and can be pushed into gaps on the end of one or more extension rods. It has a stainless steel shim on the bottom to enable it to slide smoothly.
The white contraption was designed to get levels on the underside of some roller frames. The scale can rotate in the circular holder (plastic pipe) which sits over an close fitting piece of pipe. Guides inside hold the scale vertical. The top surface of the base has a 5mm wide indent against the holder, so that any burrs on the edge of the roller frames do not put the unit out of level. Again, this was a job where you could only just reach in to get at it.Precision probing. This little device was designed to get at a precision bearing face, where the gap to get in was less than 2cm. (and at arms length). The bearing was about 90cm. diameter and the task was to set up an outer ring exactly (within 0,2mm) concentric, The outer ring was around 4 metres in diameter.
The device has a spring loaded pin on top, so that when the body is pushed against the bearing casting the pin touches the machined bearing edge first and pushes out under the spring. The body of the device keeps everything square and horizontal. At each location around the bearing (12 points in all) we set up a calibrated total station to look square in to the bearing and read the distance to the bearing. The device was then taken to the outer ring position and read again, the difference being the offset of the ring from the bearing. When all was complete shim sizes were calculated to set the outer ring truly concentric.
Fortunately, when all was done 500 ton of machinery rotated without the slightest sign of any vibration.
Last one!
This device enables verticality to be measured underwater to 1mm accuracy. It was designed for use in competition swimming pools.
One of the problems of putting the spirit level underwater to measure at the required 0.8 metres below water level is that any variation in tile fixing higher up can push the spirit level away from the wall. The orange blocks on this device offset the level by 10mm from the tile face, so it cannot catch on anything. The top target is set back by 10mm. so it represents the tile face position at the depth being measured..This also means that measurements can be taken with timing pads in place, without the frame of the pad catching on the spirit level.
The bottom plate has a plastic cage inside, which has been shimmed up to give the exact offset (third image).chris mills, post: 441643, member: 6244 wrote: cannot catch on anything. The top target is set back by 10mm. so it represents the tile face position at the depth being measured..This also means that measurements can be taken with timing pads in place, without the frame of the pad catching on the spirit level.
We “did” a pool recently, fortunately just before the pads were installed, to cut back the tiled ends to get within the 50m -0mm +30mm spec. (The photo below is just for show, we weren’t actually surveying that bit – the RMT is on the spike again, which we used and the ends to mark out the cutting line).
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