It's often impossible to read a spirit level accurately because you can't
get an eye square on to it. So are those digital readout ones any good -
and if so which one?

--
*Never underestimate the power of stupid people in large groups

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote:
It's often impossible to read a spirit level accurately because you can't
get an eye square on to it. So are those digital readout ones any good -
and if so which one?

Yes, they work quite well - though ones with an artificial 'bubble'
display in addition to a simple number are a good idea.

Dave Plowman (News) wrote:

It's often impossible to read a spirit level accurately because you can't
get an eye square on to it.

Use a small mirror to read it.

So are those digital readout ones any good -

As most of you are aware, I used to work in the aerospace industry and
one of the jobs I used to do was check the taileron angles (taileron is
a half of a tail plain that can be at any angle, independent of the
other half. Unlike a tail plane that has to be at the same angle as the
other side and creates the roll by using ailerons on the wings.)

In the old days, we used to use pantographs to measure the angles, which
were quite accurate. Then we moved on to digital angular measures. They
became the biggest pain in the arse. 0.1 degree could be the difference
between pass and fail for the test.

Make your own mind up about them, if you want that much accuracy.

Never having seen one, another thought is, how do you calibrate one?

Dave

On Mon, 07 Jan 2008 22:27:10 +0000, Dave wrote:

Never having seen one, another thought is, how do you calibrate one?

Presumably the same as you'd check a bubble one set it on an adjustable
surface take a reading, rotate 180 deg, take a reading adjust surface so
that read is half way to the previous one, rotate again, repeat until the
reading doesn't change between rotations. If you can't get the reading not
to change between rotations no matter what you do with the surface it
means the sensor is not correctly aligned to the base.

--
Cheers
Dave. pam is missing e-mail

In article ,
Dave wrote:
Dave Plowman (News) wrote:

It's often impossible to read a spirit level accurately because you
can't get an eye square on to it.

Use a small mirror to read it.

In the particular instance which prompted this post it was rather dark
inside the place I was trying to get a level so I was already holding a
torch. An LED readout would have solved both those problems.

So are those digital readout ones any good -

As most of you are aware, I used to work in the aerospace industry and
one of the jobs I used to do was check the taileron angles (taileron is
a half of a tail plain that can be at any angle, independent of the
other half. Unlike a tail plane that has to be at the same angle as the
other side and creates the roll by using ailerons on the wings.)

In the old days, we used to use pantographs to measure the angles, which
were quite accurate. Then we moved on to digital angular measures. They
became the biggest pain in the arse. 0.1 degree could be the difference
between pass and fail for the test.

Make your own mind up about them, if you want that much accuracy.

Most spirit levels are only as accurate as the person reading them anyway
- so I wasn't looking for super accuracy.

Never having seen one, another thought is, how do you calibrate one?

Unless you're talking a decent one they're fixed anyway.

--
*I finally got my head together, now my body is falling apart.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
Dave wrote:
Dave Plowman (News) wrote:

It's often impossible to read a spirit level accurately because you
can't get an eye square on to it.

Use a small mirror to read it.

In the particular instance which prompted this post it was rather dark
inside the place I was trying to get a level so I was already holding
a torch. An LED readout would have solved both those problems.

So are those digital readout ones any good -

As most of you are aware, I used to work in the aerospace industry
and one of the jobs I used to do was check the taileron angles
(taileron is a half of a tail plain that can be at any angle,
independent of the other half. Unlike a tail plane that has to be at
the same angle as the other side and creates the roll by using
ailerons on the wings.)

In the old days, we used to use pantographs to measure the angles,
which were quite accurate. Then we moved on to digital angular
measures. They became the biggest pain in the arse. 0.1 degree could
be the difference between pass and fail for the test.

Make your own mind up about them, if you want that much accuracy.

Most spirit levels are only as accurate as the person reading them
anyway - so I wasn't looking for super accuracy.


No Dave,

Spirit levels are only as accurate as the actual bubble.

If you get a poor quality level then the 'bubble' seldom 'touches' the line
and *that* leads to guesswork and inaccuracy - or simply a level that isn't
long enough for the job.

As a matter of interest, good quality levels usually have bubble adjustment
screws fitted as standard.

Brian G

In article ,
Brian G wrote:
Most spirit levels are only as accurate as the person reading them
anyway - so I wasn't looking for super accuracy.


No Dave,

Spirit levels are only as accurate as the actual bubble.

And the person reading them. Same as many things. Not all will judge
accurately when the bubble is *exactly* between the lines as well as some.

If you get a poor quality level then the 'bubble' seldom 'touches' the
line and *that* leads to guesswork and inaccuracy - or simply a level
that isn't long enough for the job.

I don't think I've got one where the bubble is *exactly* the length of the
distance between the lines. Including a couple of pricey ones.

As a matter of interest, good quality levels usually have bubble
adjustment screws fitted as standard.

Yes - I realise that. But most don't.

--
*24 hours in a day ... 24 beers in a case ... coincidence? *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Liquorice wrote:
On Mon, 07 Jan 2008 22:27:10 +0000, Dave wrote:


Never having seen one, another thought is, how do you calibrate one?


Presumably the same as you'd check a bubble one set it on an adjustable
surface take a reading, rotate 180 deg, take a reading adjust surface so
that read is half way to the previous one, rotate again, repeat until the
reading doesn't change between rotations.

It's surprising the number of people that don't know how to do that :-(

If you can't get the reading not
to change between rotations no matter what you do with the surface it
means the sensor is not correctly aligned to the base.

TBH I can't see how that could happen. Unless it is in cal.

Dave