How to Buy a Land Surveying, Construction, Aluminum, Wood, or Fiberglass Tripod
When purchasing a Construction or Surveying Grade
Tripod there are several different options to chose
from, the material, the head, the clamps, and these
are just standard options. The type of surveying
tripod you need to buy will depend on the instrument
it will support and the work conditions or
environment. With this article, we have put together
helpful information to assist in deciding what the
best options are to meet your needs.
Remember, the most important option on a land
surveying grade tripod is the thread size. This will
determine if the tripod is compatible with your
instrument or not. Most surveying instruments and
tripods have a 5/8 X 11 thread which is standardized
throughout the land surveying equipment industry.
The Material
The most common materials for surveying tripod legs
are aluminum, wood, and fiberglass.
Wood is the most traditional material for
tripods and is also the most stable, as wood is not
highly affected by temperature changes. Make sure to
get a wooden tripod with a good protective coating.
Plastic coating is preferred, but both plastic and
paint coatings will work well. Wooden tripods are
most ideal for extended setups, and will have the
least variance over the course of the set up.
Aluminum tripods are usually inexpensive and
lightweight, making it ideal for light use when
set-ups are often changed. Aluminum is not affected
by humidity. Being a metal, aluminum can slightly
expand and contract due to temperature changes.
Aluminum tripods provide the most ideal for setups
that only last a short period of time, say an hour
or less. Aluminum tripods are more economical,
light-weight, and also long-lasting. They are ideal
for leveling applications.
Fiberglass is one of the most popular choices
of surveying tripods. Fiberglass tripods are fiber
reinforced material that has minimal variance due to
temperature changes. Fiberglass is resistant to the
elements and provides a very strong and long-lasting
surveying tripod.
The Tripod Head
The tripod head is just that, it's the top of the
tripod and is a surface for the surveying instrument
to rest on and mount to. There are two head options
available, dome or flat. This is mainly just a
difference of preference. Both heads will do the
same functions and work well with most surveying
instruments. Circular dome are ideal for compensated
instruments and lasers. A flat head surveying tripod
is without a question the most popular tripod on the
market today.
The Clamps
On a surveying tripod, the clamps hold the legs in
place when they are extended.
Quick Clamp Tripods - can be set quickly.
Simply extend the legs to the desired height and
flip the lever. This will lock the legs in place.
Some surveyors prefer not to use the quick clamps
because if something accidentally catches the lever
it could unintentionally unlock the clamp. Quick
clamps do feature a bolt to adjust how tight the
clamp will lock. Quick clamp tripods are great if
your work requires frequent and multiple set ups.
Screw Clamp Tripods - To use a screw clamp
set the tripod to the desired height and
hand-tighten the screws to the desired tension. The
screw can be located on the center or on the side of
the clamp. Screw clamps take a little longer to set
up but cannot be accidentally unlocked easily, which
helps protect heavier surveying instruments from a
collapsing tripod. We also recommend screw clamp
tripods when the user plans to use heavier
instruments like robotics, total stations, or GPS
equipment since the screw clamps get tighter and
theres less chance of a clamp slipping loose and
causing a tripod to fall over damaging the
instrument.
Combination Clamp Tripods - Some tripods have
both a quick and a screw clamp that can be used
together at the same time or separately.
Heavy or Lightweight
Another important factor to consider is the weight
of your instrument. Each tripod will list a
recommended maximum weight. Even if tripod will
support the weight of the item if the surveying
instrument is too heavy for the tripod it could
cause it to warp over the time of the set up and
cause the measurements to be inaccurate.
Tripod Stabilization
When working on slick surfaces like finished
concrete or indoors, you'll want to buy a tripod
stabilizer. Tripod stabilizers come in several
styles. One style of tripod comes with a strap that
is routed through a loop or bracket on each leg
which is tightened and this keeps the three tripod
legs from spreading apart. Another style of tripod
stabilizer is one the user places on the ground or
floor and its a triangle that has three holes in
each vertex, where the tripod feet tips rest in,
which keeps the tripod legs from spreading.
The Tripod Feet
The feet probably suffer the most wear and tear of
all the tripod components. Some tripods offer
replaceable feet. This way if anything does happen
to the feet you can just replace them with out
having to replace the whole tripod. There are also
optional feet covers available for indoor use. When
steel tips become more of a hazard than a help. The
covers provide a good slip resistant base for the
tripod. And, as most land surveyors know, the feet
need to be strong for pushing into the ground to get
a stable set-up.
Hopefully with this document we have helped get your
thought process going in the right direction when
selecting a new surveying tripod. If you have any
questions, please feel free to ask us.
Copyright 2008 EngineerSupply