Hi,

I've been considering getting one of these for a while, but was
confused by the different models and the lack of basic detail in the
ads for them.

I finally splashed out on one and now I know what makes it tick, I'll
try and describe it...

There were three types on offer, a £9.99 one with a tape measure and
two
different models types with the same makers name at £19.95. This was in
Boyes at Whitby, if anyone I only looked at the latter two. Type 1 only
seemed to produce an horizontal line and made no mention of 'pendulum'.
Both boxes suggested better than 1mm per metre accuracy and a range of
100ft. So I grabbed type 2 which offered both for the same money, with
not much idea of how they worked.

It came in a small yellow plastic suitcase style box, with laser head,
tripod, a set of batteries and a small (very) instruction leaflet.. The
tripod had single leveling bubble on it which was much further out than
my own guess at level, other than that it was more than adequate to the
job. Three lockable slide out legs for rough height adjustment, then a
crank out top section for the final accurate height setting. Together
they allow for around 18" to 65" of height setting.

The laser head screws on top with two more bubble levels and three
micro level adjusters, to enable you to get the head level. I wasn't
impressed with it at this stage with its potential or reproducable
accuracy at all, though it seemed not too far out. Once the cells were
in and the unit turned on, I found it had two laser beams produced from
two diodes, producing a wide fan of vertical and horizontal line (both
around 100 deg wide), about a 1mm wide.. Each separately switched so
you could use H or V or H and V combined. The head once set for height,
can be just rotated 360 deg, to place a H or V line anywhere on any of
the four walls, calibrated around the base in degrees.

Then I glanced through the leaflet and found that a transit bolt had to
be undone to enable the internal pendulum to swing free. The twin laser
system is co-mounted on a pendulum - able to swing around 5 degrees, so
all my efforts to get the head perfectly level using the bubbles had
been a waste of time - my eyeball level would have been near enough. So
far as I could tell, the beams spead is produced entirely by lenses,
rather than any moving parts. So the line produced is quite dim and not
much use out of doors in daylight.

Brilliant piece of DIY kit :-)
I then checked the accuracy of the vertical and horizontal lines
against my engineering level (accurate to .000 something mm per metre)
and found it to be as near as I could tell spot on, on both axis.

The above level was one I used with various lengths of wood to get some
dado level in place a few weeks ago, so I checked the dado with the
laser. According to the laser level, I had drifted about 3mm during the
long frustrating process of transferring levels around the hall, around
doors and stairs etc..

--

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