Verifying and Adjusting Gantry Square

A square gantry is critical for accurate cuts and consistent part quality. Even small deviations can cause tapered parts, mismatched joints, or dimensional errors. This procedure outlines how to check and adjust gantry squareness using homing switches, test cuts, and physical verification.

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Step 1 – Preparation

1. Power up the machine and ensure motors are enabled.

2. Check homing switches: Verify both left and right switches trigger consistently.

3. Inspect the gantry: Look for loose bolts, worn bearings, or mechanical play before testing.

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Step 2 – Test Cut for Squareness

1. Load a simple program to cut a large square (at least 12" × 12").

2. Cut the square on flat scrap material.

3. Remove the part and check:

   • Diagonal measurement: Use a tape or calipers to measure both diagonals.

     • Equal diagonals → gantry is square.

     • Different diagonals → gantry is out of square.

   • Edge angle check: Place a machinist’s square or framing square against each corner.

     • If the edges align tightly with the square, your gantry is accurate.

     • Gaps indicate out-of-square or torch misalignment.

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Step 3 – Adjust the Gantry

1. Loosen bridge bolts slightly to relieve mechanical stress.

2. Identify which side needs adjustment:

   • If one diagonal is longer, that side of the gantry is trailing behind.

   • The homing switch on that side needs to be adjusted forward or backward to change the stop point.

3. Adjust the homing switch:

   • Move the home switch screw slightly so the gantry stops earlier or later.

   • Small changes make a big difference — adjust in tiny increments.

4. Re-home the machine:

   • Both sides of the gantry will contact their switches.

   • The new switch position will bring the gantry into closer alignment.

5. Tighten the bridge bolts while the gantry is held against the switches.

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Step 4 – Re-Test

1. Cut another square.

2. Measure diagonals again and check edges with a physical square.

3. Repeat (loosen bolts → adjust switch → home → tighten → test cut) until both diagonals match and all corners are square.

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Additional Suggestions

1. Laser Pointer or Dial Indicator

• Mount a pointer or indicator on the torch carriage.

• Jog diagonally across the table and check for consistent alignment.

2. Reference Plate

• Keep a “reference square” part cut when the table was last known to be accurate.

• Use it as a quick gauge during future checks.

3. Maintenance Routine

• Verify gantry squareness monthly or after any collision, rail adjustment, or major service.

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Quick Reference Procedure

1. Cut a 12" × 12" square.

2. Measure diagonals → confirm equality.

3. Check each corner with a physical square.

4. If out of square:

   • Loosen bridge bolts.

   • Home both sides.

   • Tighten bolts.

   • Test cut again.