Modelling a Spanner in CATIA V5: A Comprehensive Guide

Welcome back to our CATIA Design Series! In this installment, we’re taking on a new challenge: designing a spanner using the Sketcher Workbench in CATIA V5. Whether you're just getting started with CATIA or looking to expand your skill set, this step-by-step guide will introduce you to essential commands and techniques you can apply to your designs. 

Ready? Let’s get started! 

Step 1: Setting up the design 

Just like any other project in CATIA V5, the first step is to set up our workspace.  

1. Navigate to the Start menu, click Mechanical Design, and select Sketcher Workbench. 

2. Name the part "Spanner," make sure the Create a Geometrical Set box is checked, and save the part. 

Next, we need a reference point to base our sketch on: 

1. Click the Point option in the Reference Elements Toolbar and leave the XYZ components as zero. 

2. To start sketching, click the Sketch Toolbar, select Position Sketch, and choose the YZ plane for planar support. 

Your Task: Draw a horizontal axis using the Axis Command from the Profile Toolbar, setting the length to 250 mm. This will serve as the base for our spanner sketch.  

Step 2: Drawing the Circular Ends 

The spanner has two circular ends that we’ll draw next.  

1. Using the Circle Command, draw two circles on either end of the horizontal axis. 

   - Left circle: Radius 40mm 

   - Right circle: Radius 30mm 

Next, we’ll offset these circles to create a gap between the main and inner parts of the spanner: 

1. Select the Offset Command and apply an offset of 15mm to the left circle and 5mm to the right circle.  

Step 3: Connecting the Circular Ends 

The two circular ends are connected by a straight section in the middle, with curved transitions on either side. 

1. Select the Profile Command and draw a straight line between the R40 and R35 circles. 

2. To smooth out the connection, select the Tangent Arc option in the Sketch Tools Toolbar to curve the profile. 

3. Update the arc radius to 30mm and set the vertical distance of the straight line from the axis to 10mm. 

Quick Tip: If the arc isn't fully constrained, use the Constraints Command to define the tangency between the arc and the circle. 

Step 4: Mirroring the Connector 

To complete the connection, we’ll mirror the line to the other side of the horizontal axis: 

1. Select the line and both curved ends while holding the Control key. 

2. Use the Mirror Command and select the horizontal axis as your reference. 

Now, remove any unnecessary curves using the Quick Trim Command from the Operation Toolbar to ensure a clean design.  

Step 5: Adding an Elongated Slot 

The spanner also has an elongated hole at the center: 

1. Select the Elongated Hole Command from the Profile Toolbar. 

2. Place the start point of the slot on the horizontal axis and set the end point 120mm away. Set the slot’s radius to 6mm. 

3. Define the distance from the start point to the vertical axis as 65mm. 

Challenge: Try adjusting the slot’s dimensions to see how it affects the overall design. Explore different placements for a custom variation of your spanner! 

Step 6: Designing Grooves 

Now, we’ll add grooves to the circular ends of the spanner.  

1. Draw a Vertical Axis through the center of the R30 circle. 

2. Create a small circle (radius 1.5mm) that coincides with this axis. 

Next, trim the upper part of the circle using the Quick Trim Command. Now it’s time to replicate the semicircle: 

1. Select the Rotate Command and set the number of instances to 24. 

2. Click on the center of the R30 circle and the semicircle, then set the angle to 15°. 

Interactive Task: Experiment with different instances and rotation angles to see how the groove pattern changes! 

Step 7: Adding Additional Details 

To add more detail, we’ll draw two parallel lines connecting the outer and inner circles of the spanner: 

1. Using the Line Command, draw a line from the outer to the inner circle, constraining its height from the center axis to 10mm and the angle to 20°. 

2. Draw another line parallel to the first, with a length of 43mm. 

Once the lines are in place, use the Quick Trim Command to clean up any excess curves.

Step 8: Finalizing the Sketch 

With the main features of the spanner complete, it’s time to review and finalize: 

1. Use the Sketch Solving Analysis tool to check if all curves are closed. If any are open, it may be due to the rotated features not being fully constrained.  

2. The diagnostic tab might show some under-constrained areas, but the geometry is ready for creating a solid model. 

Now click the Exit Sketcher Command to finalize the sketch. 

Congratulations! You’ve just completed a detailed spanner design using CATIA V5. From drawing circular ends to adding grooves and elongated slots, you’ve learned a variety of commands that can be applied to many other designs. 

Challenge for You: Try applying what you’ve learned to other tools or components. Can you design a wrench or a hammer next? The possibilities are endless once you master CATIA’s Sketcher Workbench. 

This blog is part of our ongoing CATIA Design Series. If you missed the previous posts, check them out here

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