All About transit levels

All About Transit Levels and Their Parts

A transit level is essentially a telescope securely installed upon a tripod base, but it's so much more than that. Surveyors and builders use levels for establishing clear plumb lines, estimating distance and elevation, and determining the relative positions of objects.

Large Components of a Transit Level

Whether you're curious about how they operate or need to replace a part, read below to get all the details about transit levels and which roles their parts play.

Telescope

You'll use this the majority of the time to gaze through the eyepiece and twist the cylinders horizontally to focus on a particular target.

Graduated Leveling Vial

This is embedded in the top of the telescope and is the traditional bubble spirit chamber that you see on old-style levels. When the bubble is centered within the guidelines, you know you've reached a level point.

Verniers

Verniers are what allow the angles to be read and interpreted. Double verniers create the ability to read angles in multiple directions.

Base Plate

A necessary contact point between the telescope and the tripod, the base plate creates stability for your level.

Alidade

This is an all-encompassing term for the entire upper section of the device. It includes the telescope, its supports, leveling vials, spindle, and circle-readers.

Small Components

These may need to be replaced more often due to their frequency of use.

Focusing Knob

Located at the larger end of the telescope, this allows you to customize your view for crispness and clarity. If the subject is fuzzy or washed out, rotate the focusing knob and the image should resolve.

Tangent Knobs

If the readings from the main scale are too small to make out, use the tangent knobs to specify and confirm your angular readings. You will find one for both horizontal readings and vertical readings.

Eyepiece

Located at the opposite end of the telescope from the large lens, its cylinder can be twisted to bring the crosshairs into greater focus.

Leveling Screw

Adjust this component if you find that the alidade is askew from the tripod base. No need to take anything apart, just gradually twist the screw until you find a level spot again.

How to Choose a Tripod

Consider these aspects of a tripod to support your transit level. 

Choose Your Material

First, choose a material that is lightweight and durable, such as wood, aluminum, or fiberglass. Wood is the least expensive, and won't be affected by temperature changes. Aluminum is also affordable and weighs less than wood, to accommodate quick changes in setup and transportation. Fiberglass is probably the most sturdy but is slightly more expensive.

Ensure Stability

Next, think about how to keep your tripod stable. Land and terrain are almost never perfectly flat. You need a tripod whose legs can be customized independently of one another and whose feet are stable. Self-adjusting hinges and rubber O-rings help with this process.

Decide Height and Weight Needs

Further, consider your height and weight requirements. You are likely to be carrying your tripod and level around for most of the day. The heavier it is, the more of a burden it is, even if it is more stable once it is set up. Telescoping legs can be a way to customize the height of your tripod. Think about the overall stability, however. The higher your tripod goes, the further your level may fall.

Work Within Your Budget

Finally, establish a budget for your tripod and work within it. A top-of-the-line model may do everything you need it to, but at the same time, you may be paying for more than you need. Aluminum is probably the best combination of lightweight, affordability, and durability.

Frequently Asked Questions