GX-55: 2D blade trim calibration on a grader

How to properly adjust for blade wear slope calibration

Log in or sign up for myTopcon to view this page:

GX-55: 2D blade trim calibration on a grader

Issue: Slope not matching

The moldboard's cutting edge, bolted along the bottom of the moldboard and along the sides, should be straight or true. Rock and soil will eventually wear down the center of a cutting edge, causing it to cup.

As the cutting edge on your grader wears, the Topcon slope sensors will require a calibration in order to maintain slope accuracy.

It's inevitable; eventually, a cutting edge will need to be replaced. However, it is important to keep your blade calibration current and accurate. 


An operator says, "I cut a 2% going one way, then turned around, and the blade is under cutting or leaving grade fat." 

This issue is almost always associated with a calibration issue and can typically be rectified using the blade trim function.

Calibration process

On the control box, press the Topcon logo. Go to Control > Blade calibration > Blade trim.

Enter in a slope value using the arrows or by pressing in the white area and using the calculator.

Choose a slope percentage which will allow you to move some material across the entire width of the moldboard.

Follow instructions on the screen: "Make a smooth pass with right side in auto," controlling the opposite side by hand.

Once you are satisfied you have a good smooth pass, press Next.

Turn the machine around, grading over the first pass. Your slope will now be falling in the opposite direction of the first pass.

Slowly make a pass over the previously graded area, and ensure the entire machine is set within the cut grade.

Stop the machine, and slowly lower your non auto (left) side by hand until it touches the grade.

With the arrow buttons, raise or lower to allow for the automatic side of the moldboard to match grade.

Once you have made any necessary adjustments, press Next.

The last screen will show you the total adjustment which was made to the slope sensor. Press Finish prior to moving the machine forward.

Note: You may notice the blade either raise or lower a slight bit after pressing Finish. This is because this calibration process will take out half of the slope error due to cutting edge wear. 

If your slope adjustment was out a significant amount, you may need to perform this calibration again.