Summary

Print one of these bit tray covers, put a rubber band or velcro strap around it, and you can throw your bit tray into the bottom of your tool box and not have the bits come out and make a mess! Truly awesome. I had five sets of bits so I labeled them with a paint marker.

Fully parameterized model in .FCStd format, created using FreeCAD 0.21.1

Custom Section

Not all bit holders are the same size, as I realized as I started making this cover for four sets of bits in what turned out to be trays with three different dimensions. So rather than upload an STL file that might or might not be the right size, I am uploading my model in .FCSTd format for FreeCAD. The model is fully parameterized - all you have to do is go the spreadsheet "Params" and enter the dimensions appropriate to your bit holder tray.

The key parameterd are all internal dimensions of the cover, since those are the external dimensions of the bit holder tray and are easiest to measure. These are shown in the TechDraw page of the model, with dimensions labled with the parameter names from the spreadsheet. The key dimensions are:

Length - this is the full length, end to end, of the bit tray
Large and Small diameters - these are the diameters (not radius) of the radiused ends of the bit tray
Internal depth - this is the height of the bit tray w/ bits. Adjust by subtracting for an exposed brim at the bottom if desired.

The external dimensions are then calculated based on desired wall thickness. I made the bottom wall thickness a separate parameter.

I used 2mm wall thickness and 3mm bottom wall thickness, and I printed in PLA just because it is what I had installed and dialed in on my printer.

Cover for bit-set tray