Theodolite?

That's great, I'd not heard of Harbour Freight so I'd never have found that. I downloaded the instructions.

Many thanks, and to spades and JIMRAT.

Harbour Freight is my "go to" store for inexpensive tools that I may only use once, but are nice to have. Or, sometimes nice to have and may never use.

I buy lots of casters and small wheel/tire sets for use on our small equipment at work.

And, I have a store 1/4 mile from my house.

I don't use Harbor Freight, so I wouldn't have found it either. As Lyn stated, they are great for 'inexpensive' tools. But, I never skimp on the ones I use for measuring/aligning. K&E use to be my go to, and still is if I can get the older stuff. You have to be careful with K&E stuff in the 80's and after. With bankruptcies and numerous acquisitions and licensing of the Trademark... it might say "K&E" but question its quality and do your due-diligence.

Not saying all of it is suspect... I got a really good K&E Optical Transit in the mid-90's from Cubic Precision. Cubic Precision made some killer optics. In fact when Brunson bought Cubic, they scrapped their optical tooling for that of Cubic's. Note, that Brunson stopped using the K&E name so KEUFFEL & ESSER CORPORATION is no more... RIP my dear friend.

Anyway... I would not recommend using that for anything critical. Want to hang pictures at the same height on the opposite sides of the room... likely good enough.

They are bloody useless.

The bubble is not level, as you rotate the head it bobs and weaves, the "laser" pointer is not parallel to the level. It was a total waste of money.

I bought a couple of these with the idea of attaching them to my wheels to align them, The red dot would project onto a wall at a distance, measure the space between and then do it again with a plank/stick at 1m. Do the maths to get toe in. Use a hoist to get camber etc. BUT the bloody red dot is about 5mm dia and very fuzzy. Over a distance it was no where near as accurate as my dumpy. At 20M i can read a tape measure through my dumpy with enough clarity to see 1/2mm, with the "laser level" the dot had spread to over 1cm and moved about (fuzzy). Yours may be a better brand than my far east variety, but basically it is a cheapo laser level.

Jim

To my knowledge it should be a Dumpy Level.

DHAYANANDHAN.S

This be a theodolite - (not with two legs)

Well, depending on the age, I would call that green thing a transit, just like the one I have in my office (but it's orange-different manufacturer) and use on occasion. The one pictured is a lot newer than the ones I learned on.

As for the OP photo, its a very poor substitute for a good old fashioned dumpy level.

The Harbour Freight version is sold in the UK as the Power Master Laser Level Kit. A set of instructions for operation is available on google by typing in Power Master Laser Level Instructions.

Not a theodolite,but much more accurate.

An old tried and true method of finding level is a water level.

It was used to lay out the pyramids.

The modern version,which I have made and used,consists of a jug of water and the

required length of flexible clear hose.

A coloring agent can be added to the water to increase visibility.

The tube or hose is filled with water by siphoning,ensuring there are no air bubbles in the line.

The jug is placed on a stationary platform,the level above the platform is precisely

marked on a rod or stick.

Attach the tube to the rod.

The rod is moved to any point of interest,and when the level stabilizes,it will be exactly the same as the level in the jug.

Read the miniscus of the water for precise results.The miniscus is the center of the

water column,not the edges touching the tube.

If,for instance,you are laying out the foundation for a building,mark your corner rods at this level.

You now have a reference mark for all 4 or more corners that will be exactly level

with each other.

Now pull a string from each of the corners for your mason to use.

The mason will be impressed with the accuracy of the level line.

Far superior to a string level.

Very inexpensive and reliable as gravity.

True, the miniscus can be concave or convex,that is why it is important to use the miniscus,as I stated, not the side of the tube for measurement.

Google miniscus images for examples of both concave and convex.

I don't know of any framing carpenter that can cut his wood within the limits of the meniscus. Or a mason laying bricks. Deadly accurate over that crummy laser level.

My father built houses, when a 2x4 was really 2"x4". Any measured and cut board was usable if it was within 1/4 inch when cut to length. Doors, windows and cabinets were the exception.

I worked with an older engineer who would give a measurement as either neat, skinny or fat.

If he told you it was a fat 3/8" you cut it a bit past the line, a skinny one was a bit before the line and if neat you were to leave half the line in place after the cut.

It worked just fine for what we were doing at the time.

Around here,(south of the Mason-Dixon line),the carpenters use this steel tape.

Even apprentices know intuitively how to use it.

Very accurate.

Warning:

Link might not be suitable for all viewers,use discretion.

http://ls1tech.com/forums/racer-s-lounge/1407013-new-stanley-tape-measure.html

If you really want to split hairs with the water level,add a few drops of non-foaming

detergent to the water,and incline the tube at the final resting point of the liquid.

This allows you to "stretch out" the final height of the liquid.

The detergent reduces the surface tension of the water,and reduces friction with the

tube walls,which actually creates the miniscus effect.

Insofar as the convex or concave portion of the miniscus,one should wait for the level to stabilize,neither rising or falling, before taking a reading.

The great thing about the water level is that any error is non accumulative,as

opposed to the laser level,which will get worse the further you get away from the

source.

It's not a "true" Theodolite. It's more of a cheap Contractor's or layman's tool to use for leveling and rough grading purposes. You also need a second body holding a Surveyor's rod or some other type of graduated measuring stick near to plumb.

In order to achieve any degree of accuracy, you need to know how to set it up for "LEVEL" 360-degrees just like you would with a Surveyor's Transit, level, and Theodolite. That takes some actually hands-on practice.

There's many Youtube videos that show you how to set up a surveyor's instrument.

It's equivalent to a spirit level, but difficult to get 'level'.

Works perfectly on the drawing board and in the instructions. But not much use elsewhere.

It's one (similar) tool I bought thinking it would be useful for setting out shelves and worktops and cupboards on my narrowboat - but problems in setting it up meant the results were not much better than guesswork. It was abandoned and not used - the level that is.

OK, Folks. I WAS going to answer this one, but you've covered all the bases. That model looks like it cost too much money for what it'll do, but my daughter used/uses hers to hang pictures, which, I too, think is about all they are good for.

So, I can't add anything to this discussion. But I CAN learn something.

What in the world is a "Dumpy Level"? I've never heard the term before. Forgive my ignorance, and please enlighten me.

And, oh, yeah. I, too, have used the "bottle and hose" level. And they DO work wonderfully.

Thank you.

Me, too.

Wiki says; The transits of the early 20th century had a horizontal circle and often had both a vertical circle and a spirit level. They could be considered as a universal instrument that both could do the work of a theodolite and that of a dumpy level. The main difference between a theodolite and transit of that day though was that a transit could transit. By taking readings then transit the telescope, rotating it 180 degrees around both the horizontal and vertical axles, and taking readings again and calculate the average values you could rather simply eliminate almost all instrument errors except for if the vertical axis of the instrument wasn't being vertical. Johan G (talk) 20:46, 10 August 2009 (UTC)

Dumpy= level/transit = angles

Thanks, Lyn. Still not sure I get it, though. Which part, and why, is Dumpy? The transit, or the level?

BTW, my Dad used to use theodolites on a bridge construction crew, when the bridges they built were literally built by hand (big tough guys passing 8X12 timbers overhead from member to member while straddling a piling in the middle of the river. Not for the faint of heart.) and I used to work with an engineer (logistics specialist) who earned his way through college walking track for the SP RR and surveying (with a theodolite) potential new trackage layouts.

Handy, but not something I'd use for hanging pictures and such around the house, I think. Of course the ones they used would set you back thousands of dollars, nowadays.

Can't find an origin for the name. Not that of the inventor, for sure.

My dad worked for the National Park Service building bridges on high mountain trails in the Sierra Nevada Mountains in CA. That was 1954.

They rode horses to most sights and everything was done by hand.

The family camped out there one summer while he worked. Sequoia, Kings Canyon, Atwell Mill and Mineral King are names I still remember. What a grand summer for us kids.

The "dumpy level" got its colloquial name from the short (ie dumpy) viewing scope that is part of its structure.

They are more correctly known as Gravatt levels after the inventor and later as Troughton levels after one refiner of the design

Thank you. NOW I get the picture. And since both you and JimRat are in Oz, my guess is that the term isn't well known here in the other end of the world. I know I never heard it before. But I have seen the devices of which you speak.

It's just that most of my work with a level has been with a 3 or 4 foot bubble level. I personally have never built a bridge (at least not a long span automobile bridge) and haven't needed anything more than that.

Thanks again, gents. I keep coming back to CR4 because EVERY time I can't offer insight to the OP, I learn something new from those who do. And most of the time even when I can offer insight I learn something new.

As a volunteer, with a small band of others (all unpaid) we helped build a local community centre many years ago. We muddled by.

The building inspector said we did a good job in getting the elevations right - very impressive!. "Did you use this laser light?" he asked. "No!" I said "I used theodolite".

Actually, we had a 'tame' surveyor who set the prime datum points with his Dumpy level from which we set other levels as we needed them.

Dad used to do transits on his theodolite.

No doubt. This is all outside my area of understanding.

A "dumpy" level is sold as an "automatic level" by the makers. Google it and you will see images. 20 yrs ago a good one cost around $1200 Au then laser levels were introduced and soon came down in price to match the dumpy. No more dumpy sales so they in turn came down in price and are now sold for $500 Au.

A good one is basically a 24x telescope that can focus up close ( the better the quality the closer it can focus ) on a rotatable platform/plane that is parrallel to the line of sight. It also must have the means to make the platform level and then stay level throughout the rotation. Usually a round bubble level. A good one will have a suspension system inside to prevent ground vibrations (from traffic etc.) from shaking the view, and a means to adjust the level ( not to be done b the user ), and also internal adjustability to the suspension and compensator mechanisms.

I had to reset mine as the previous owner/s had messed with them. I used a water level to mark out points in my shed to achieve this. My water level was 20M long and so i used a garden hose and added clear beverage tube to each end. No need for a bottle. It is just a long 'u' tube manometer.

Jim

"No need for a bottle. It is just a long 'u' tube manometer."

True...You don't need a bottle - however one of the difficulties encountered when using a water level is the accidental spillage that occurs if you hold one end of the tube a bit low or a bit high, and this happens regularly as the water moves quite rapidly and overshoots considerably when finding its level.

Whilst you generally don't lose much, it can easily be enough to change the relative levels enough to introduce unacceptable inaccuracies.

The bottle greatly overcomes this concern because it introduces a much larger reservoir as compared to the tube, and so any losses are nowhere near as problematic. If you hold the moving end high, the fluid just returns to the bottle rather than spilling out the other end, and if you hold it low, the little bit lost is readily made up by the excess in the bottle.

Always a good idea to hold your finger over the end when relocating, and then releasing gradually to prevent overshoot.

Yes you are right, you can, and do, lose some water when moving from one point to another BUT there is no loss of accuracy. The water still finds its' own level it is just further down the tube.

Jim

True, but you then need two sets of hands to use the device, and that can be costly.

It is normal practice to fix one end at the datum level and just move the other end as required.

If you lose fluid in that circumstance your levels will be inaccurate.

That pic of mine shows the bottle attached to a hook, it is simply hung on a nail with the fluid at the datum level, and then one person can do it all. A bit of lost fluid barely affects accuracy.

The bigger the bottle, the less affect fluid loss has.

O.K. I always had spare hands, paid by me of course but then i very soon had a dumpy instead. That too took two sets of hands.

Jim

The water level I made includes a valve at the none datum end (actually at both ends but the datum valve is normally left open). Closing the valve when moving between measuring points prevents the loss of any water. I used it to construct a 820m long 250mm deep 400mm wide flume for cooling blocks of ploymerized roofing bitumen. The base of the flume is accurate to 3mm along the whole length so that the speed of the water and the buoyant moulds (tubs) into which the bitumen is cast remains consistent. As the water moves it carries the tubs along, think in terms of an industrial version of 'pooh sticks'. The surface of the water is 80mm higher at the start of the flume so the tubs float downstream. As the level reduces the water speed increases (conservation of energy rule) so that any resistance to movement a block has from the preceding block is minimal. Part of the flume is in the form of a 104m long raised steel tank (1m long U shaped troughs bolted together on legs) so that cooling air can flow below the channel to assist the natural cooling. The remainder of the flume is in a channel cut into the concrete floor of the mixing and pouring building which also houses two roofing felt production lines. The tank has four lanes where the blocks flow back and forwards twice to reduce the overall footprint of the plant. When full the flume carries 1600 blocks (40 tonnes) and nominally 80m³ of water all driven by one throttled back 3Kw pump that draws water from a level control weir at the end of the flume and transfers it the start of the flume which is only 2m away. At the end of the flume the blocks are lifted out of the water on a conveyor, flipped over to eject the block into a palletiser, and the empty tub is conveyed back under the pouring head ready to be released back into the start of the flume for another 14 hour cooling cycle. The whole operation is fully automatic with only two operators required to supervise the process, monitor the computer controlled product mixing, and remove fully loaded pallets. Plastic draped over the tub before the bitumen is poured deforms into the tub to create both a release agent and the packaging. When the block of bitumen comes to be used it is melted in a mobile mixer and the packaging plastic is incorporated into the mix as part of the polymerized bitumen mix that is poured onto flat roofs.

Always reestablish your datum point before a job,and verify no bubbles in the tube.

That method corrects for any fluid loss due to evaporation,etc.

If you are really paranoid about it put a small pocket mirror behind the miniscus to eliminate parallax error.

The only numerical errors will be caused by the initial measurement and subsequent measurement from the datum point.(Human error). The actual error will be near zero.

A small tube will allow more time to set up each point,because in a long line,it will move very slowly due to internal resistance.

If you have many points to mark the delay is sometimes cumbersome,so size the hose accordingly,and keep an eye on the miniscus.

Do not mark until the miniscus has stabilized..

When storing,plug or valve off the end of the tube and seal the source to reduce evaporation.

I have seen them made with oil instead of water and they work just as well.