Electrically Isolated FeedThrough for Lightning Arrestor

thingiverse

I needed an insulated feed through for an antenna lightning arrestor I'm building for shortwave radio use. The STLs as presented are specific to my application, but I am including the FreeCAD file as well, in case you need to modify it to fit your own needs. As is, the feedthrough is designed according to these specifications: * Screw size is M4. * The mounting hole is drilled out to 11/32 inches. * The material is 2.5 mm thick. * The shoulder is 18.75 mm in diameter. To modify this for your own needs, you only need to change the parameters in *Sketch* under *bushing*. The four constraints you need should be red. There are two construction lines - one for the thickness of the walls and one for the diameter of the screw. The shoulder diameter and the material thickness are modified on the actual drawing. If you are interested in the lightning arrestor itself, it's just a scrap piece of aluminum angle into which I've drilled and tapped three holes appropriate to the spark plugs I'm using. It doesn't really matter what type spark plug you use. I'm just using three used NGK BMP4ES plugs that I pulled out of mowers I've worked on. Wrap a solid wire from one screw (fed through the feedthrough) around each of the three plugs and back down to the other feedthrough. You can solder the wire to the plug caps if you want, but as long as you wrap it tightly, I don't think it's really necessary. The whole assembly is then mounted and somehow grounded. I plan on killing two birds with one stone by mounting the block to a steel pole that I will drive into the ground. Your antenna comes in and attaches to one side while your radio attaches to the other side. --- **NOTE** *Due to either a Thingiverse bug or (more likely) shadowbanning, my models no longer show up under the [Newest] listings. If you want to see more of my models, please be sure to 'follow' me. **If you print this, it would really help if you'd post a 'make' so that others could find this model**.*