Sunday, February 18, 2024

Lightwave portable magnetic stand for Elecraft KX3 and PX3

Elecraft KX3 is a fantastic portable transceiver but one thing I thought could be improved is using a better stand to the stock, foldable legs. 
The built-in foldable feet are a bit annoying as they require the user to manipulate the thumbscrews holding the radio together and because they are opposing, this needs to be done in different directions when standing in front of the radio, not to mention that the front panel sits at too low of an angle for my taste.
I decided to design a lightweight stand that has small footprint, and it can be assembled or taken apart in seconds in the field and will give a good support for the radio without the need to completely unfold the stock legs.
It was a quick and fun half-day project.

The two legs of the stand were designed with TinkerCad and then 3D printed.

All of the components for the stand - the 3 spacer rods and the 2 legs. 
The weight is exactly 2oz. but there is a room to shave off some of it in the next version.

Inside the holes for the carbon-fiber spacer rods, I glued small neodymium magnets (source eBay - 1/4" x 1/8" N42 type). I made a "bed" for friction-fit of each magnet which has a slightly smaller diameter than the main hole, matching the inside diameter of the rod. All magnets are also glued in their "beds" in the same orientation (polarity) by adding a drop of Super Glue before pressing the magnet in place.
The tricky part is to get right the size of the main opening of the arrow-shaft receptacle. Arrow shafts come in different "spine" level or amount of flexing. This is controlled by the manufacturer with the thickness of the arrow-shaft wall or more specifically, the outside diameter - stiffer shaft (lower spine number like 350) will have a larger outside diameter than a 600 spine. Furthermore, when 3D printing the plastic also shrinks as it cools so it takes some experimentation to get the size just right for a snug fit that will also afford smooth and effortless assembly / disassembly.  

For the spacer rods I used scrap cut-offs from carbon fiber arrow shafts. These are very strong and lightweight tubes and bonus they have quite nice finish. 
I have a whole bunch of these pieces in varying lengths leftover from sizing of my archery arrows.
 Inside each of the arrow shafts I glued the same size neodymium magnets, making sure that the polarity is the opposite of the ones in the legs. The glue was applied on the perimeter of the magnet and then inserted into the arrow shaft, making sure it is perfectly flush with the end of the tube.

The stand can be assembled together literally in seconds. The spacer rods just snap firmly in place and hold the entire stand together. Disassembling is just as easy by pulling everything apart. 
The magnet-to-magnet attraction provides just the right amount of holding force without making it difficult to pull apart. 

The original foldable legs of the KX3 can be unfolded ever so-slightly to lock the stand in place so the radio cannot move sideways. This is not really necessary as the stand's legs fit between the stock legs rubber booths, but it can provide additional support if needed.

The angle of the front panel with the radio on the stand is not as low as with the original foldable KX3 legs. 
The radio sits angled at exactly 45 degrees which I find to be more ergonomic.

Short video of one-handed assembly of my KX3 stand.
 A set of shorter rods can turn this stand into a PX3 stand (the KX3's Panadapter). This stand also works great as a portable cell phone stand and I'll be making another one for use during my air travels or when using the cell phone for logging in the field.

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