Dumpy/site levels

[Vijay]

Hi,

Any tips on what to look for when buying one? I'm looking for one for setting out work and if I end up doing groundworks myself.

There's so many on Ebay/Amazon starting from £100 + but any features I should definitely be including when buying?

Just watched a couple of YouTube videos and a laser receiver seems a good idea and a must if working on my own

Thanks

Vijay

Edited June 24, 2016 by Vijay

[TerryE]

We've just got a basic one which is fine for what we needed.  IMO, the bells and whistles are only worth while if you are doing a lot of level taking.  You don't even need a laser receiver to work on your own if you make a cross T support and velcro your sighting rule to it; you just need to walk to and from the dumpy each measurement, which is fine if you are just doing the odd level check.  But if you do buy a second hand dumpy, then you must make sure that it's properly calibrated -- a bit of a faff but easy enough to do.

As to what to look for, try to make sure that its "only one owner / one project" preferably with the original boxing still intact.  I'd avoid a knocked around builders hand-me-down.

[Crofter]

I've got a fairly cheap and basic one, was about £100, does the job. I gave up getting SWMBO to hold the staff, and took to sticking a pinchbar in the ground and strapping the staff to it with a bungee. Easier methods may be available!

[Jeremy Harris]

47 minutes ago, Vijay said:

Hi,

Any tips on what to look for when buying one? I'm looking for one for setting out work and if I end up doing groundworks myself.

There's so many on Ebay/Amazon starting from £100 + but any features I should definitely be including when buying?

Just watched a couple of YouTube videos and a laser receiver seems a good idea and a must if working on my own

Thanks

Vijay

It very much depends on what you want to do.  A dumpy really needs an assistant to hold the staff, and needs to be set level carefully before you start, so may not be ideal for working on your own.  Working outside on your own a good self-levelling rotating laser level with a receiver on the staff means you can quickly set out levels around the whole area swept by the laser and the receiver saves a lot of faffing about trying to see the line.  A standard laser level should be a Class 2, good for +/- 3mm over 30m, which is OK for most levelling work on site, like drains, base of foundations etc, and just about OK for finished floor levels.  Watch out for second-hand units that have had a hard life, it's easy to damage things like the self-levelling system on some of the cheaper ones. 

My personal view is that a decent self-levelling Class 2 accuracy rotating beam laser plus a good surveying tape is probably worth buying new, but that for setting out on a position-sensitive site, or one where there is a slope or a few immovable obstacles around you may be better off getting several accurate 3D positions fixed with a Total Station and then making sure those datum points are protected so that you can work from them.  You can do accurate setting out from known datum points with just a tape and a bit of Pythagoras, and be sure that you have got an accurate result by measuring in closed loops, with reverse measurements on every distance and then applying a least-squares correction to the loop to average out the errors.

 

[Vijay]

Anyone know if these are any good? http://www.ebay.co.uk/itm/ROTARY-RED-LASER-LEVEL-TRIPOD-STAFF-5-DEGREE-RANGE-ALIGNMENT-SELF-LEVELING-/231715205939?hash=item35f34d7333:g:KEgAAOSwI-BWF1wa

[Vijay]

Terry, I took a detour through Ashton today, I looked out for a self build but couldn't see any going on

[JanetE]

That's because we're in Hartwell opposite the pub

[Vijay]

That could be why then lol I haven't ventured to Hartwell yet

[ToughButterCup]

1 hour ago, JSHarris said:

[...]

Working outside on your own a good self-levelling rotating laser level with a receiver on the staff means you can quickly set out levels around the whole area swept by the laser and the receiver saves a lot of faffing about trying to see the line.  A standard laser level should be a Class 2, good for +/- 3mm over 30m, which is OK for most levelling work on site, like drains, base of foundations etc, and just about OK for finished floor levels. [...]

  You can do accurate setting out from known datum points with just a tape and a bit of Pythagoras, and be sure that you have got an accurate result by measuring in closed loops, with reverse measurements on every distance and then applying a least-squares correction to the loop to average out the errors.

I'm eight weeks away from having to get this right for myself. And so I'm looking up at this new learning curve with a good deal of trepidation. Up for it, but scared a bit.

All I need to sort it out for myself is an authoritative reading list, and some sensible suggestions about buying the right kit. I have done a good deal of background reading, and looked at YT videos. Wary, as ever, of online shared ignorance, would someone start me off, please?

• Reading which explains a good bit  more than the basics
• An example of a sensible bit of kit

Please?

[Vijay]

I'm about to order one of the laser levels I posted a link to, anyone know a reason why I shouldn't??

[Jeremy Harris]

17 minutes ago, Vijay said:

I'm about to order one of the laser levels I posted a link to, anyone know a reason why I shouldn't??

Have you looked at the accuracy?  It's pretty rubbish, +/-1mm over 1.5m, so over a 30m distance it's going to be +/- 20mm (or up to 40mm total error).  It also has no mention of any accuracy class or certification, so I strongly suspect it's a cheap Chinese import that may well not even meet the advertised spec in practice.

If it were me I'd look for a certified Class 2 one, which will be guaranteed to be no worse than +/- 3mm over 30m, a heck of a lot better than that ebay one.

[Vijay]

I did notice that and have already emailed the seller to ask. I suspect you're totally right though

[Jeremy Harris]

The give away is the location, Portsmouth.  Hundreds of Chinese sellers drop ship from Portsmouth, and they don't make it clear on their ebay ad that you are really buying from China directly, so have no protection under UK consumer law, just whatever protection ebay offers (not much). 

I got involved in helping someone fight a legal battle over a Chinese seller drop shipping illegal goods from Portsmouth a few years ago.  A lady had bought an electric bike from ebay, thinking she was buying from a UK seller.  She was stopped by the police because the "electric bike" turned out to be an electric scooter with pedals fitted, but which couldn't be used to propel the thing.  The police were trying to prosecute her for riding a motor vehicle with no registration, insurance or road tax and I got involved trying to advise as to whether the scooter met either the UK or EU definition for an electric bike (certain electric bikes are legal, many are not). 

In her case the scooter was very definitely an electric scooter and it proved impossible to make it legal, as there was no way it could have been made to pass the single vehicle type approval scheme and then be registered and insured.  She tried to take action against the seller, but it turned out that despite being advertised as being in Portsmouth the seller was really in Shenzhen, China.  Trading Standards got involved, but were powerless to help, as it was effectively a direct purchase from China, despite having been drop-shipped from a Portsmouth warehouse (even that wasn't accurate, it actually came from a warehouse at Southampton Docks).  The police decided not to pass the case to the CPS, but advised that the scooter had to be broken up, which it was.  It was a very sorry tale, as the lady had spent all her savings on it, and in getting legal advice.

[PeterW]

This isn't a bad deal but either needs 2 of you or a leg on the staff !

http://www.ebay.co.uk/itm/CST-BERGER-24X-AUTOMATIC-AUTO-DUMPY-SITE-LEVEL-FULL-KIT-/222163208091?hash=item33b9f5879b:m:mQZDuHd5DiRb8bOG7OkBuOA

[ToughButterCup]

9 minutes ago, JSHarris said:

The give away is the location, Portsmouth.  Hundreds of Chinese sellers drop ship from Portsmouth, and they don't make it clear on their ebay ad that you are really buying from China directly, so have no protection under UK consumer law, just whatever protection ebay offers (not much). 

 

'... drop ship...' means?

[Declan52]

Boat drops anchor, handbrake turns, throws all the cheap Chinese stuff overboard and is back pointing homewards before customs have had a chance to inspect.

[Vijay]

47 minutes ago, JSHarris said:

The give away is the location, Portsmouth.  Hundreds of Chinese sellers drop ship from Portsmouth, and they don't make it clear on their ebay ad that you are really buying from China directly, so have no protection under UK consumer law, just whatever protection ebay offers (not much). 

I got involved in helping someone fight a legal battle over a Chinese seller drop shipping illegal goods from Portsmouth a few years ago.  A lady had bought an electric bike from ebay, thinking she was buying from a UK seller.  She was stopped by the police because the "electric bike" turned out to be an electric scooter with pedals fitted, but which couldn't be used to propel the thing.  The police were trying to prosecute her for riding a motor vehicle with no registration, insurance or road tax and I got involved trying to advise as to whether the scooter met either the UK or EU definition for an electric bike (certain electric bikes are legal, many are not). 

In her case the scooter was very definitely an electric scooter and it proved impossible to make it legal, as there was no way it could have been made to pass the single vehicle type approval scheme and then be registered and insured.  She tried to take action against the seller, but it turned out that despite being advertised as being in Portsmouth the seller was really in Shenzhen, China.  Trading Standards got involved, but were powerless to help, as it was effectively a direct purchase from China, despite having been drop-shipped from a Portsmouth warehouse (even that wasn't accurate, it actually came from a warehouse at Southampton Docks).  The police decided not to pass the case to the CPS, but advised that the scooter had to be broken up, which it was.  It was a very sorry tale, as the lady had spent all her savings on it, and in getting legal advice.

That sounds totally crazy that the Police couldn't see it for what was a decided to prosecute and dispose her savings

[Jeremy Harris]

44 minutes ago, recoveringacademic said:

 

'... drop ship...' means?

OK, the "system" (some might say scam.......) works like this.

- You are a Chinese-based retailer and you do not want that fact to be known to your customers, because you know that UK buyers will pay more, and place greater trust, in a UK-based seller.

- You rent a bonded warehouse in the UK and pay a UK agent to ship goods from that warehouse to addresses you pass to that agent, and pay UK VAT and duty as required, for a fee.

- You advertise on ebay as if you are based in the UK, giving the location of the goods as being the warehouse location (roughly).  This is legit under ebay rules.

- You collect payment in CHINA, via ebay, so as far as the law is concerned this is an overseas purchase, not covered by UK/EU consumer protection law, and the goods do not have to comply with any safety regulations.

- As soon as a sale is made the goods are shipped by the third party agent (who is not legally the retailer, as he/she has not advertised or sold any goods) to the buyer.

- The buyer has a problem and then finds that they have purchased direct from China, in effect, and so have no recompense except under ebay rules or Chinese law.

 

[Vijay]

Bit naughty for Ebay to allow overseas sellers to advertise as UK location then  But at least they tend to have good customer services when it comes to problems with sellers.

[Jeremy Harris]

It's highly unethical, in my view, but ebay is ebay and will do what it wants, pretty much. 

The other give away that an apparently UK based seller is really in China is to ask some questions and see what time of day you get a reply.  It's usually pretty easy to spot Chinese based sellers as they respond overnight and at weekends, when the majority of UK businesses will be closed.  The use of "Chinglish" in the reply or advert can also be a good clue!

[Vijay]

lol Chinglish - perfect word to describe a reply!!!

[Nickfromwales]

22 hours ago, PeterW said:

This isn't a bad deal but either needs 2 of you or a leg on the staff !

http://www.ebay.co.uk/itm/CST-BERGER-24X-AUTOMATIC-AUTO-DUMPY-SITE-LEVEL-FULL-KIT-/222163208091?hash=item33b9f5879b:m:mQZDuHd5DiRb8bOG7OkBuOA

Good spec for the money. 

I think I'd be inclined to go for the Bosch 3 line as it's got good accuracy over 50+ M's and its just so bloody handy for so many other jobs on the rest of the build. 

Do the 'dumpy' sets give distance or just level? I've never used one tbh.  

[Declan52]

High tech (expensive) can do distances but mainly used for level. If it's just to put levels at the start then I would just hire a good one and make a few marks on site that everyone else can take levels from.

[Jeremy Harris]

On 24/06/2016 at 20:34, recoveringacademic said:

I'm eight weeks away from having to get this right for myself. And so I'm looking up at this new learning curve with a good deal of trepidation. Up for it, but scared a bit.

All I need to sort it out for myself is an authoritative reading list, and some sensible suggestions about buying the right kit. I have done a good deal of background reading, and looked at YT videos. Wary, as ever, of online shared ignorance, would someone start me off, please?

• Reading which explains a good bit  more than the basics
• An example of a sensible bit of kit

Please?

Sorry, missed this.

The level that Peter W linked to is good value, a well-known brand and accurate (+/- 2mm over 1km when reversed and corrected).  When surveying it's normal to shoot angles (in 3D, so levels too) in both directions.  So you take a set of readings from point A to point B, then swap over the level and staff and take a reverse reading.  You then use an averaging method to correct for errors.

The surveying I used to do was down caves, to plot out in 3D where the approximate centre of passages was, with section sketches at each station.  A level wasn't easy to use underground, so a lot of the time we just used a short staff and a hand-held sighting compass and inclinometer, together with a Fibron tape.  You'd take forward and reverse readings from every station and stick them in a notebook.  We used to try and always work in closed loops if we could, often using previously surveyed bits at the start and finish.  A correction technique was applied to get the smallest loop closure error and the most common was to use the total least squares method (see here: http://eprints.soton.ac.uk/263855/1/tls_overview.pdf ).  There are other methods and for just two points you can average the readings to get a slightly better result.  The accuracy given for the level that Peter W linked to refers to the standard deviation using the averaged error between two points, I believe.

For site setting out then I suggest that hiring kit to set a few datum points, as already suggested, then using a reasonable (Class 2 accuracy) laser level with staff and receiver, together with a decent surveying tape, will be fine.

[PeterW]

1 hour ago, Nickfromwales said:

Do the 'dumpy' sets give distance or just level? I've never used one tbh.

Yes using the Stadia Lines on the eyepiece - most have a 100 multiplier so are easy to read. Not entirely accurate but good enough for basic point finding.

This guy explains it in less than 2 minutes..!