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My printer (using Cura) will automatically print a thin support in the void where I want to put the nut. How can I selectively not print in the void where the nut will go?
In terms of strength. I simply put a solid tube around the bolt. 1/16th" (1.6mm) thickness is what my printer prints before putting an air gap. This tube will not compress much. If one tube is not strong enough. Add more concentric tubes with an air gap between. Or an asterix (spoke like) pattern of internal walls.