K6ARK Pico Paddle

BACKGROUND: 

The Palm Pico Paddle is infamous amongst portable CW operators for its small size, good feel, and cool retractable case.  Unfortunately, they have been out of production for years, and they sell for much more than their original retail price on the used market. 

But now, you can make a 3d printed paddle for just a few dollars in parts that feels and performs much like the original. 

Parts are kept to a minimum, and total cost per unit is very small. Set screws allow independent adjustment of the throw.  Tension is fixed and is based on how much you fatigue the levers to soften them up.  The 3.5mm TRS jack allows connection to your radio with any standard Aux cable.  

There are holes to press in 4x 4 mm x 2 mm magnets and one 10 mm x 2 mm into the base of the key to stick it to a ferrous object.  If you can find a source for 14 mm x 4 mm oval silicone rubber feet, they'll add grip.  If not, you can use silicone or urethane adhesive to fill the holes and make some grippy pads. 

The base plate has a slot to attach the plate to the side of a Mountain Topper radio.  The key will attach to the base plate from the bottom or either side to give multiple mounting options.  

Here's a little video about how the paddle works, and how to disassemble and maintain it. 

BILL OF MATERIALS:

Links are Amazon Affiliate links - It costs you nothing more, but I get a few cents on the dollar from Amazon if you purchase through these links. 

TOOLS:

• 3d Printer capable of printing PETG
• 1.5 mm hex driver (https://amzn.to/3gX4sB8 or https://amzn.to/3ulV3X1)
• #1 Phillips head screwdriver (https://amzn.to/3HaQlD2)
• Tweezers (https://amzn.to/3BaOeex)
• Wire cutters or scissors you aren't worried about damaging (https://amzn.to/3VycZJK) 
• Soldering iron (optional - you can build the paddle without this) (https://amzn.to/3P3bxgk)

ASSEMBLY: 

1.) Print all the things.

I've included the GCode I use on a Prusa i3 Mk ii if you want to just download and hit “print.”

Print your parts for the assembly.  Use PETG only!  This design relies on the flexibility and elastic deformation capability of PETG.  PLA will not work. 

Supports are necessary under the lever arms, and are helpful under the case ends. 

You may need to clean up the openings of the bottom holes on the base plate to get the magnets in if your first layer height results in some elephant's foot spreading.  

2.) Strip away all supports and clean up the prints.

3.) Bend the levers back and forth 45-60 degrees to soften the flex.

I usually do this about 30-50 times to significantly soften the spring tension of the levers. 

4.) Scuff sand the bottom rounded edges of the lever base, and the inside of the case walls.

Cleanly printed PETG has a relatively high coefficient of static friction on itself.  Light scuff sanding helps the sliding action. 

5.) Attach 15mm of wire to each side lug of the connector.

If you don't have a soldering iron, you can tightly twist the wire onto the connector with tweezers.  You may notice degraded contact over time, but this can work well enough. 

6.) Install the connector into the lever print. 

Gently use the tweezers to bend the ground lug of the connector (the center one) if needed. The ground lug needs to be on the bottom of the jack, but will flex upward to sit on the round screw post. Use the threaded ring to secure the jack it into place.  Screw the M3 machine screw into the round post, clamping down the lug of the jack.

7.) Install the wires and set screws.

Insert the wires into the small holes on the top of each lever until it is visible in the cross-hole.  Screw the set screws into the holes ensuring they make contact with and capture the wire.  Screw the set screws in until the outer head of the screw is flush with the outside of the lever. The wire should be long enough to avoid impeding movement of the lever. Bend it out of the way on top of the lever ensuring it does not short out to the ground lug of the jack. 

8.) Install the levers in the case. 

Watch the video above for technique and orientation.  Press the cover on.  Test the key for proper function.  If it does not function properly, disassemble as shown in the video and check for continuity from the tip and ring of your cable to each set screw. 

9.) Press the two 10 mm magnets into the base and install the rubber feet into the base plate.

10.) Install the key into the base plate. 

Watch the video for instructions. 

Have fun with your new K6ARK Pico Paddle!