3D print of "legs" for mounting brackets

Wed 2025/11/12 3d-print 3d printing / openscad

Overview

• repo status: Repo Information
• installation: Common Setup

Summary

This project creates "legs" using openscad for mounting PCBs using the PCB brackets.

To run

See doc/test_process.md to do the initial install.

And then do these steps:

• run openscad
• load the .scad file
  • click "File"
  • click "Open File"
  • navigate to the directory
  • click Open
• render it by doing one of these (the image will go all yellow):
  • click Design | Render
  • press F6
  • or, click icon with cube and corner arrows
• export it by doing one of these:
  • click File | Export | Export as STL
  • press F7
  • or, click icon with page and "STL" on it
• navigate to this directory and save the .stm file into ./out directory

In your 3d printer (see below for Bambu Studio):

• import the .stm file from ./out
• slice it
• print it
• check if it fits on your PCB and bolts fit correctly, etc.

If it works for you, and you're using a BambuLab A1 Mini, do these steps to create a few more brackets:

• open Bambu Studio
• import the stm file into your 3D printer
• ensure you are in the "Prepare" tab
• right-click on the model
• select "clone"
• click "+" 3 times to get a total of 4 brackets on the plate
• select them: press ctrl and then click on each of the 4 brackets
• right-click on the plate (not the model)
• select "arrange"; Bambu Studio will move and orient the 4 brackets for efficient printing
• click "Slice plate"
• click "Print plate"
• get a "Send print job" dlgbox
• click "Send"

To use the legs

Note: this is for 6-32 bolts! The holes are small enough that the bolts can be self-tapping. So using other size bolts may cause issues.

calculate the number of legs you need to stack

To calculate the number of stacked components do this:

• Take the length of the bolt e.g. 1"
• divide by 1/4" => 4
• this will have the bolt stick out from bottom of the feet long so that bolt extends out and a nut can be used to hold into a bottom plate/board.
• if you want to have the PCB rest on the "feet", then you want the bolt to not extend out out and to be inside the bottom foot. If so, subtract 1 from the stack. e.g. num_stacks => 4 - 1 = 3

Note: In the the bracket_legs_v2.scad, I used:

• 1/2" bolts with the bolt staying inside the feet
• so 1/2" / 1/4 = 2

num_stacks = 2; // works for 6-32 x 1/2" bolt inside

to use a leg

• for each leg, screw the bolt into the leg separate from the bracket. This helps get the self-tapping to work correctly without putting extra unnecessary force on the bracket or the leg.
• unscrew the bolt
• put the bolt through the hole in the bracket
• screw the bolt back into the leg.
• repeat for all 4 corners of the PCB

This shows 1/2" legs for the 6/32/ x 1/2" bolt:

Next steps

• create versions for 3M (metric) and other common bolt sizes