Transit Level Component Parts and How They Work | Engineer Supply - EngineerSupply

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All About transit levels

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.

All About transit levels

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.


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 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.


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.


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

What Is a Transit Level?


Commonly used in many trades such as construction, surveying, architecture, landscaping, and excavation, transit levels are optical precision instruments that provide a quick snapshot of reliable data for planning your job.

How Is It Different From a Builders Level?

Transit levels move both horizontally and vertically to capture the correct angle and distance. A builder's level can only be manipulated horizontally in a complete circle.

What Does a Rotary Laser Level Do?

Rotary lasers spin a beam of light rapidly enough to fully measure a spherical space, either horizontally or vertically. They are typically used outdoors, with a receiver / detector.

How Do I Read a Transit Level?

Manipulate the vertical and horizontal axes until the crosshairs provide a reading. Use the horizontal tangent knob to tilt the telescope sideways, and use the vertical tangent knob to tilt it up and down.

How Do I Set Up My Transit Level?

Make sure your tripod is set up in a secure location, then bolt the telescope to the tripod. Make sure to remove the lens cap and provide a sunshade if it is bright.

Rely On Us for All Your Surveying Needs

Browse our appealing collection of transit levels and component parts. We are an authorized dealer for all the parts we sell. We source our parts directly from the manufacturer and offer a USA warranty guarantee.

Best Transit Levels

David White LT8-300P


One of the most important factors to consider when it comes to picking out a level is accuracy. This means that you want to make sure you are investing in a piece of equipment that will deliver on this front. The David White LT8-300P is one such example. The design features a horizontal circle with lock and tangent. Additionally, it also has a vertical arc with lock and tangent. It can read up to 400 ft, which makes it an excellent fit for far-distance scenarios.

Northwest Instrument Transit Level NSLP500B


When it comes time to picking out a level, you want to make sure that you are picking one that will be simple to use right away. The Northwest Instrument Transit Level NSLP500B is a transit laser level that is specifically designed for ease of use. The level can be used for a variety of applications, meaning that it is a great fit for whatever you might be trying to achieve. Plus, the durable design of the level makes it an item you can trust in no matter what the demands of your next project might be.

David White LT8-300LTU-LP


Visibility is incredibly important when it comes to the tool you pick to survey property. If you can’t see the readings on the device, then whatever you are being told will not be able to help you much. Thankfully, this is not an issue you will encounter with the David White LT8-300LTU-LP. Whether you’re looking to tackle vertical or horizontal sightings, this is a model that will be able to help you. The solid three-piece tool is as durable as it is useful and boasts a number of impressive features.

Johnson Level 22X Builder's Transit Level


Whether you’re trying to dig out a foundation, install a patio, or add new floors to a building, you need to make sure that your transit level for sale is equipped for the job. From looking over the evenness of anything from curbs to fences, you can easily tackle whatever construction tasks are in front of you with the Johnson Level 22X Builder’s Transit Level. A durable and reliable tool that can be used with ease no matter how experienced you are with this type of item.

SitePro 25-TL20X


When you’re trying to complete a job, you want things to go as fast as possible without sacrificing quality. The SitePro 25-TL20X is a great example of an option that will deliver results right from the start. With a simple to use interface and built-in sunshade, there are a number of features that are sure to impress with this device. No matter how long you’ve been working in your industry, you can be sure that this is a great fit to consider.

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