Stephen Davies from Team Unlimbited created an excellent spreadsheet to help determine the optimal scaling percentage for e-NABLE hand devices.
You can download a copy of the in either Google Sheets format or Microsoft Excel format here.
Just enter the values for the Recipient’s Measurements (Width of Hand and Length of Hand) in cells B24 and C24. The spreadsheet will then update automatically. Refer to the matrices to determine the best scale for the device type you’re making.
Use this as a general guide, but be sure to carefully examine the specific values in the matrix for the hand type you’re producing. In some cases, a close fit for hand width is more important than a close fit for hand length (i.e. for shorter hand lengths).
For example, a recipient with no fingers may have a hand width of 80mm and a hand length of 80mm. Referring to the Raptor Reloaded sizing matrix, the colored “Confidence %” bar would seem to indicate that 85% is the best scale. In fact, you’d probably be better off with a 125% scale, which would fit the hand width properly. Having some extra length in the device won’t be a problem, but a device that is too narrow would be.
Arm devices require additional measurements. For making the UnLimbited arm, just enter the measurements into the Thingiverse Customizer here. For the Flexy Arm and other arm devices, the spreadsheet above and Blender method below will help you find the best scaling factor.
For another effective method for determining the proper scale for an e-NABLE device, check out Peter Binkley’s excellent YouTube Tutorials for taking good sizing photos and using the free Blender software tool to determine the optimal sizing.