I did an instructable on building a Balun or Unun. A lot of people seemed to like it and it get getting repined in every bodies emergency go pack or field day kit bag. Since those boxes were out of stock I went to the Home Depot to see what kind of PVC electrical boxes they had.
There's a good selection but the boxes with no holes start around $8. Some of the ones with a conduit fitting molded in are under $2. No easy way to plug that without a big protrusion so I decided to make use of them.
Step 1: Custom 3D Printed Bushings
I made some bushings in OpenScad for some common parts like an SO-239 and some binding posts. I grabbed a bunch of different boxes with different configurations and some covers. I used PLA material and it seems to bond well to the boxes with standard PVC Conduit Cement.
Step 2: SO-239 Bushing
This was the first one I needed. I made a small relief for a ground wire under one of the screw holes. A little RTV will seal it but since I usually have this one pointed down I don't worry about that....
Step 3: 1/4-20 Posts for Wing Nuts
These are pretty solid posts with a 1/4-20 hole down the center for a standard bolt. Use Stainless hardware if you are bored. I just use some automotive dielectric grease on the exposed metal. I bet a shot of Battery terminal spray after your wired up would work too.
I made these with a 50% infill and 6 shells to make them stiff enough to handle my overenthusiastic wrench use. maybe I'll make a recess for the nut on top but I do like to "KISS"
You can strap this to the top of a pole and hang an inverted Vee directly off the terminals.....
Step 4: Binding Post Bushings
Just a hollowed out version of the wing nut bushing. Good for light duty use or small go packs.Much prettier than the wing nuts but I wouldn't hang a dipole off these without some other support. The hollow and thin brass will snap.
Step 5: Other Uses
There are tons of other uses I can think of. Pilot lights, switches, headphone connectors, etc.
These tiny bushings have a ridge on top that can hold standard wire strain relief fittings. I used one on the power cord of this simple knife etching power supply.