This 3D-printed caliper extension is designed to enable measurements of concave, hard-to-reach surfaces (such as the middle of the palm) using a standard digital caliper. I had to make this out of necessity to measure my palm thickness that was difficult to measure with flat caliper jaws. This design allows for a soft, rounded end that can be used on soft-surfaces by providing some additional lateral space.

NOTE: PLEASE USE THE UPDATED PLATE (with simpler but more accurate design)

• 30 mm lateral offset between jaws (15 mm per side)
• Additional 5 mm reach from the caliper ruler to the measurement tips

To use: mount the extensions, bring the tips together, tare the caliper to zero, and then measure normally.

This version is dimensioned specifically for NEIKO digital calipers (commonly available on Amazon). If you are using a different model, you may need to scale the parts to fit your caliper’s jaw geometry.