Lathe tool holder
thingiverse
Print the part with 5 contour lines. That way the part that has to take most of the forces is strongest. I've only drawn the left part. The right part can be mirrored in the slicer software.
Download Model from thingiverse
With this file you will be able to print Lathe tool holder with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Lathe tool holder.