Ever designed a 10mm peg and a 10mm hole, only to find they absolutely won’t fit together after printing? 3D printers rarely print exact nominal dimensions due to plastic shrinkage, extrusion width, and cooling.

This simple, practical calibration tool helps you find the exact real-world tolerances of your specific printer, filament, and slicer settings. Print this before you start designing mechanical assemblies to save hours of redesigning!

🔍 What’s Included

The test includes four nominal sizes (20mm, 15mm, 10mm, and 5mm) featuring:

• Matching Plugs/Pins: Designed at exact nominal diameters.
• Incremental Hole Clearances: Six test holes per size, ranging from +0.10mm to +0.60mm offsets.

📊 Real-World Test Results (What to Expect)

During my own testing, I found that smaller features shrink proportionally more than larger ones. Here is how the fits usually break down:

💡 Key Takeaway: Don't design solely on nominal dimensions. If you need a 20mm shaft to rotate freely, you likely need to design the hole at 20.20mm. If it needs to be a tight press-fit, a 20.00mm hole might be perfect right off the bed.

⚙️ How to Use This Model

1. Print the model using your standard slicing profile and favorite filament (PLA, PETG, etc.).
2. Test the pins in the various clearance holes.
3. Take notes on which clearance yields your ideal Press Fit, Removable Fit, and Sliding Fit.
4. Apply these offsets directly into your CAD models for perfect mechanical parts on the first try!

Note: Results will vary based on your nozzle size, layer height, material type, and flow rate. Run this test whenever switching to a vastly different material (like PLA to TPU or ABS).

🚀 Download & Support

If this tool saves you filament and design time, please leave a ⭐⭐⭐⭐⭐ review and post your makes with your printer settings to help the community!