Came across this just now whilst looking for a new spirit level:
http://www.dm-tools.co.uk/product.ph...n//sn/CHH50024
Looks like it would be much easier and quicker to read accurately than
a bubble, though the 'ball' looks a little vulnerable. Has anyone seen
or used one of these in the flesh? 37 quid is a lot to spend if it's a
piece of junk.

(As this reads a bit like one of those 'just found this great blah
blah blah' spams, I should point out that I actually found it on eBay,
item 320427322254, but d+m tools has better pictures, and of course I
have nothing to do with either seller)

pcb1962 wrote:
Came across this just now whilst looking for a new spirit level:
http://www.dm-tools.co.uk/product.ph...n//sn/CHH50024
Looks like it would be much easier and quicker to read accurately than
a bubble, though the 'ball' looks a little vulnerable. Has anyone seen
or used one of these in the flesh? 37 quid is a lot to spend if it's a
piece of junk.

(As this reads a bit like one of those 'just found this great blah
blah blah' spams, I should point out that I actually found it on eBay,
item 320427322254, but d+m tools has better pictures, and of course I
have nothing to do with either seller)
I cannot believe anyone can read the angular position of a 35-40mm
sphere to the same accuracy as a spirit level.
A decent level will show the difference of a piece of thin card inserted
under the end of a level. So that is about 0.5mm in 600mm - better than
1 in 1000.

Pure gimmick I reckon.

Bob

On 18 Feb, 18:42, pcb1962 wrote:

Looks like it would be much easier and quicker to read accurately than
a bubble,

No, it's ********. It doesn't have the vernier effect of a long,
shallow bubble. These things are _easy_ to read, but far from
precise. 5 degrees would be lucky.

On Feb 19, 8:46 am, Bob Minchin
wrote:
pcb1962 wrote:
Came across this just now whilst looking for a new spirit level:
http://www.dm-tools.co.uk/product.ph...n//sn/CHH50024
Looks like it would be much easier and quicker to read accurately than
a bubble, though the 'ball' looks a little vulnerable. Has anyone seen
or used one of these in the flesh? 37 quid is a lot to spend if it's a
piece of junk.

(As this reads a bit like one of those 'just found this great blah
blah blah' spams, I should point out that I actually found it on eBay,
item 320427322254, but d+m tools has better pictures, and of course I
have nothing to do with either seller)

I cannot believe anyone can read the angular position of a 35-40mm
sphere to the same accuracy as a spirit level.
A decent level will show the difference of a piece of thin card inserted
under the end of a level. So that is about 0.5mm in 600mm - better than
1 in 1000.

Pure gimmick I reckon.

If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up

"Matty F" wrote in message
...


If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up

Count interference rings, its easier and more accurate.


Now expect replies from the group idiots that don't understand the physics
and won't know what I mean. ;-)

On Feb 19, 9:05 pm, "dennis@home"
wrote:
"Matty F" wrote in message

...

If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up

Count interference rings, its easier and more accurate.

Now expect replies from the group idiots that don't understand the physics
and won't know what I mean. ;-)

The local university made a mercury inclinometer (without the LEDs)
and noticed that the whole city tilted twice a day because of the
tides. Auckland is between two harbours with different tide times.

Matty F wrote:
On Feb 19, 8:46 am, Bob Minchin
wrote:
pcb1962 wrote:
Came across this just now whilst looking for a new spirit level:
http://www.dm-tools.co.uk/product.ph...n//sn/CHH50024
Looks like it would be much easier and quicker to read accurately than
a bubble, though the 'ball' looks a little vulnerable. Has anyone seen
or used one of these in the flesh? 37 quid is a lot to spend if it's a
piece of junk.

(As this reads a bit like one of those 'just found this great blah
blah blah' spams, I should point out that I actually found it on eBay,
item 320427322254, but d+m tools has better pictures, and of course I
have nothing to do with either seller)

I cannot believe anyone can read the angular position of a 35-40mm
sphere to the same accuracy as a spirit level.
A decent level will show the difference of a piece of thin card inserted
under the end of a level. So that is about 0.5mm in 600mm - better than
1 in 1000.

Pure gimmick I reckon.

If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up


If you want even more accuracy get a long length of clear pipe and fill
it with water.

"dennis@home" wrote in message
...


"Matty F" wrote in message

...


If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up

Count interference rings, its easier and more accurate.


Now expect replies from the group idiots that don't understand the
physics
and won't know what I mean. ;-)


They may not be idiots, just not as well educated as you!

The H&S police would ban the mercury idea, and interferance fringes
may be a tad hard to see in some of the places that I use my spirit
level. Monochromatic light source might be tricky on a building site
g

AWEM

On Fri, 19 Feb 2010 22:13:24 +1100, F Murtz
wrote:

If you want even more accuracy get a long length of clear pipe and fill
it with water.


Unfortunately it isn't all that accurate. Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

It has the advantage of consistency across quite long distances,
though, as long as 3mm is near enough.

Bruce wrote:
On Fri, 19 Feb 2010 22:13:24 +1100, F
wrote:

If you want even more accuracy get a long length of clear pipe and fill
it with water.


Unfortunately it isn't all that accurate. Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

It has the advantage of consistency across quite long distances,
though, as long as 3mm is near enough.


It is a lot more accurate than 3mm, You don't read top of the meniscus
at one end and bottom of meniscus at other.
Also in a small tube the meniscus would be a lot less than 3mm.

"Andrew Mawson" wrote in message
...

"dennis@home" wrote in message
...


"Matty F" wrote in message

...


If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up

Count interference rings, its easier and more accurate.


Now expect replies from the group idiots that don't understand the
physics
and won't know what I mean. ;-)


They may not be idiots, just not as well educated as you!

The ones I refer to are idiots and no amount of education will change it.


The H&S police would ban the mercury idea, and interferance fringes
may be a tad hard to see in some of the places that I use my spirit
level. Monochromatic light source might be tricky on a building site
g

Lasers are cheap.
If you want accuracy on a building site you use a plumb bob, far more
accurate than spirit levels, but a bit less convenient.

On Sat, 20 Feb 2010 00:28:34 +1100, F Murtz
wrote:

Bruce wrote:
On Fri, 19 Feb 2010 22:13:24 +1100, F
wrote:

If you want even more accuracy get a long length of clear pipe and fill
it with water.


Unfortunately it isn't all that accurate. Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

It has the advantage of consistency across quite long distances,
though, as long as 3mm is near enough.


It is a lot more accurate than 3mm, You don't read top of the meniscus
at one end and bottom of meniscus at other.


Don't confuse precision with accuracy. They are two different things.

Some years ago I did a comparison of water level and precise levelling
techniques using an optical level and staff. The systematic errors of
the two methods were 3mm and 1mm respectively.

The 3mm systematic error for the water level occurred even though
users were trained always to read the bottom of the meniscus. Had
that not been the case, the systematic error would have been
correspondingly higher.

What was good about the water level was that systematic errors
remained the same over a wide range of distances. That was very
encouraging, and vindicated our choice of water levels to lay concrete
ground slabs in a 180 m x 54 m building. Precise levelling using
optical methods showed that the slabs as built were well within the
tolerance of + or - 5mm stated in the contract.


Also in a small tube the meniscus would be a lot less than 3mm.


In such a small tube, viscosity would become a greater problem.

Please don't think I am in any way criticising water levels. They are
simple and very effective. Like any method of surveying or measuring,
they have their limitations, but when used within those limitations,
they are accurate (within 3mm) and supremely reliable. And they don't
need highly trained people to operate them.

"Bruce" wrote in message
...


Also in a small tube the meniscus would be a lot less than 3mm.


In such a small tube, viscosity would become a greater problem.

I assume they don't mean a tube small enough for capillary action to occur.


Please don't think I am in any way criticising water levels. They are
simple and very effective. Like any method of surveying or measuring,
they have their limitations, but when used within those limitations,
they are accurate (within 3mm) and supremely reliable. And they don't
need highly trained people to operate them.


It needs a bit of training otherwise they will level one end and forget that
both ends move when you lift or drop one end. Sometimes with a serious
delay.

Do water levels work better if you put detergent in the water?

On Fri, 19 Feb 2010 14:01:40 -0000, "dennis@home"
wrote:
"Bruce" wrote in message
.. .

Also in a small tube the meniscus would be a lot less than 3mm.


In such a small tube, viscosity would become a greater problem.

I assume they don't mean a tube small enough for capillary action to occur.


No, but viscosity would become a problem long before capillary action
was an issue.


Please don't think I am in any way criticising water levels. They are
simple and very effective. Like any method of surveying or measuring,
they have their limitations, but when used within those limitations,
they are accurate (within 3mm) and supremely reliable. And they don't
need highly trained people to operate them.


It needs a bit of training


That's why I emphasised they don't need people to be *highly* trained.

otherwise they will level one end and forget that
both ends move when you lift or drop one end. Sometimes with a serious
delay.

Do water levels work better if you put detergent in the water?


The ones I have used have all had anti-freeze in. perhaps that has
the same effect of reducing surface tension? I would not presume to
know how best to design one, my experience has been using them
together with other methods.

"Bruce" wrote in message
...


Do water levels work better if you put detergent in the water?


The ones I have used have all had anti-freeze in. perhaps that has
the same effect of reducing surface tension? I would not presume to
know how best to design one, my experience has been using them
together with other methods.


In DIY they are more likely to be a couple of plastic tubes and a length of
hosepipe. ;-)

On Fri, 19 Feb 2010 14:16:18 -0000, "dennis@home"
wrote:



"Bruce" wrote in message
.. .


Do water levels work better if you put detergent in the water?


The ones I have used have all had anti-freeze in. perhaps that has
the same effect of reducing surface tension? I would not presume to
know how best to design one, my experience has been using them
together with other methods.


In DIY they are more likely to be a couple of plastic tubes and a length of
hosepipe. ;-)


True, I have only ever used them on construction sites except once,
when I made one according to "your" design. It worked, but I would
not have trusted it to be accurate to any better than ~ 5 mm.

On 19 Feb, 13:28, "dennis@home" wrote:

Lasers are cheap.

The cheapest laser I have that will show interference fringes in this
application is still a He-Ne (30 quid S/H these days, from
supermarket scanners). You won't do it usefully with an eBay laser
pointer module.

On 19 Feb, 12:12, Bruce wrote:

Unfortunately it isn't all that accurate. *Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

The great advantage though is that it maintains that same precision
over varying lengths, up to quite long. I wouldn't use one to put up a
bookshelf, but I still prefer it to a Cowley, dumpy or theodolite for
general DIY building work.

On Fri, 19 Feb 2010 06:50:02 -0800 (PST), Andy Dingley
wrote:

On 19 Feb, 12:12, Bruce wrote:

Unfortunately it isn't all that accurate. *Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

The great advantage though is that it maintains that same precision
over varying lengths, up to quite long.


When quoting my message, you deleted the paragraph:


It has the advantage of consistency across quite long distances,
though, as long as 3mm is near enough.


Why would you delete that, only to make the same comment yourself?


I wouldn't use one to put up a
bookshelf, but I still prefer it to a Cowley, dumpy or theodolite for
general DIY building work.


Agreed. I tend to use a Dumpy (actually a Kern) more than most people
would because (a) I own one and (b) using one is second nature to me.
It's also a bit of a collector's item, a thing of beauty, and I use it
whenever I get the chance.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "dennis@home"
saying something like:

Count interference rings, its easier and more accurate.

You mean polarised light?

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Bruce
saying something like:

Please don't think I am in any way criticising water levels. They are
simple and very effective. Like any method of surveying or measuring,
they have their limitations, but when used within those limitations,
they are accurate (within 3mm) and supremely reliable. And they don't
need highly trained people to operate them.

Exactly so. I used one to put in a floor from scratch where the level
was fairly important because of a floor-level window at one end. At the
time laser levels were still fairly pricey and this cost about 3 quid
for the aquarium air tubing. Worked a treat, and I suppose it's possible
there might be up to 3mm error, in practice it's certainly not
noticeable.

Bob Minchin explained :
I cannot believe anyone can read the angular position of a 35-40mm sphere to
the same accuracy as a spirit level.
A decent level will show the difference of a piece of thin card inserted
under the end of a level. So that is about 0.5mm in 600mm - better than 1 in
1000.

Pure gimmick I reckon.

I agree, it limited ability to even be able to read it with any
accuracy - makes it nothing more than a gimmick.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

After serious thinking Bruce wrote :
Unfortunately it isn't all that accurate. Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

It has the advantage of consistency across quite long distances,
though, as long as 3mm is near enough.

A dash of liquid soap mixed with the water overcomes the surface
tension and I don't recall ever having a problem with viscosity.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Fri, 19 Feb 2010 16:59:34 +0000, Grimly Curmudgeon
wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Bruce
saying something like:

Please don't think I am in any way criticising water levels. They are
simple and very effective. Like any method of surveying or measuring,
they have their limitations, but when used within those limitations,
they are accurate (within 3mm) and supremely reliable. And they don't
need highly trained people to operate them.

Exactly so. I used one to put in a floor from scratch where the level
was fairly important because of a floor-level window at one end. At the
time laser levels were still fairly pricey and this cost about 3 quid
for the aquarium air tubing. Worked a treat, and I suppose it's possible
there might be up to 3mm error, in practice it's certainly not
noticeable.


True. A 3mm error across a floor - of almost any size - shouldn't
present a problem.

I doubt you would get any better accuracy with a laser level.

Several years ago I tried a domestic laser level - Black and Decker -
and found it was about 10mm out over 7 metres. To make matters worse,
it was sealed and therefore non-adjustable. Annoying!

Matty F wrote:
On Feb 19, 9:05 pm, "dennis@home"
wrote:
"Matty F" wrote in message

...

If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up
Count interference rings, its easier and more accurate.

Now expect replies from the group idiots that don't understand the physics
and won't know what I mean. ;-)

The local university made a mercury inclinometer (without the LEDs)
and noticed that the whole city tilted twice a day because of the
tides. Auckland is between two harbours with different tide times.

We came across this when I was working in the aerospace industry. 8
hangars were built for the US airforce for WWII and development moved
into one.

We had to do a test called symmetry and alignment which consisted
screwing balls into designated points on the aircraft and using two
theodolights and a telescope, along with a rule to hook, or hang from
the balls to measure the straightness, or not of the aircraft. This was
done so that if it suffered exccess G or had a heavy landing, it could
be determined what had got bent, if anything.

With the hangar being fairly close to a tidal river, the concrete floor
rafts would rise and fall with the tides.

Dave

In message , "dennis@home"
writes


"Andrew Mawson" wrote in message
...

"dennis@home" wrote in message
...


"Matty F" wrote in message

...


If you want accuracy, why not use the device I just invented this
minute - a pool of mercury with a metal plate above each end. The
capacitance is measured and a row of LEDs light up

Count interference rings, its easier and more accurate.


Now expect replies from the group idiots that don't understand the
physics
and won't know what I mean. ;-)


They may not be idiots, just not as well educated as you!

The ones I refer to are idiots and no amount of education will change it.

Dennis, the common consensus here is that you are the group idiot


The H&S police would ban the mercury idea, and interferance fringes
may be a tad hard to see in some of the places that I use my spirit
level. Monochromatic light source might be tricky on a building site
g

Lasers are cheap.
If you want accuracy on a building site you use a plumb bob, far more
accurate than spirit levels, but a bit less convenient.



--
geoff

"geoff" wrote in message
...


Dennis, the common consensus here is that you are the group idiot

I know you are arrogant but do you really think you and a couple of other
idiots represents the group consensus.
I don't as they are almost certainly more intelligent than you.

In message , "dennis@home"
writes


"geoff" wrote in message
...


Dennis, the common consensus here is that you are the group idiot

I know you are arrogant but do you really think you and a couple of
other idiots represents the group consensus.
I don't as they are almost certainly more intelligent than you.


Not possible dennis


--
geoff

geoff wrote:
In message , "dennis@home"
writes


"geoff" wrote in message
...


Dennis, the common consensus here is that you are the group idiot

I know you are arrogant but do you really think you and a couple of
other idiots represents the group consensus.
I don't as they are almost certainly more intelligent than you.


Not possible dennis

Arrogant and ignorant could possibly be suitable descriptive words.

I have recently had an accident according to the guy who wears the funny
clothes in this village. I competently avoided one with forward planning.

Some of VI's recent comments have been most interesting. In his capacity as
the local jester, I'm sure that he has worn a plantpot or two.

"Clot" wrote in message
news
geoff wrote:
In message , "dennis@home"
writes


"geoff" wrote in message
...


Dennis, the common consensus here is that you are the group idiot

I know you are arrogant but do you really think you and a couple of
other idiots represents the group consensus.
I don't as they are almost certainly more intelligent than you.


Not possible dennis

Arrogant and ignorant could possibly be suitable descriptive words.

I have recently had an accident according to the guy who wears the funny
clothes in this village. I competently avoided one with forward planning.

Oh yes I forgot you intended to hit the kerb.

On Feb 20, 12:18 am, "Andrew Mawson"
The H&S police would ban the mercury idea, and interferance fringes
may be a tad hard to see in some of the places that I use my spirit
level. Monochromatic light source might be tricky on a building site
g

We've got loads of mercury:
http://i46.tinypic.com/120qi6o.jpg

"Matty F" wrote in message
...
On Feb 20, 12:18 am, "Andrew Mawson"
The H&S police would ban the mercury idea, and interferance
fringes
may be a tad hard to see in some of the places that I use my
spirit
level. Monochromatic light source might be tricky on a building
site
g

We've got loads of mercury:
http://i46.tinypic.com/120qi6o.jpg

Difficult to see from that picture - is it a mercury arc rectifier or
something more exotic?

AWEM

On Feb 20, 9:17 pm, "Andrew Mawson"
wrote:
"Matty F" wrote in message

...

On Feb 20, 12:18 am, "Andrew Mawson"
The H&S police would ban the mercury idea, and interferance
fringes
may be a tad hard to see in some of the places that I use my
spirit
level. Monochromatic light source might be tricky on a building
site
g

We've got loads of mercury:
http://i46.tinypic.com/120qi6o.jpg

Difficult to see from that picture - is it a mercury arc rectifier or
something more exotic?

Yes a mercury arc rectifier. There's a few litres of mercury in each
of four.
The power cable between the two main island of NZ uses them also, plus
the Wellington trolley bus system.

Bruce wrote:
On Fri, 19 Feb 2010 06:50:02 -0800 (PST), Andy Dingley
wrote:

On 19 Feb, 12:12, Bruce wrote:

Unfortunately it isn't all that accurate. Surface tension and
viscosity issues mean it cannot be relied on for anything more precise
than 3mm at best.

I'm confused. I see why viscosity would make it _slow_ but why would
the levels not settle down in the end? It's not as if it was grease.



Agreed. I tend to use a Dumpy (actually a Kern) more than most people
would because (a) I own one and (b) using one is second nature to me.
It's also a bit of a collector's item, a thing of beauty, and I use it
whenever I get the chance.

This is why I use a Cowley. It was my grandfather's.

Andy