Step 1: Cut the 6mm shaft as you need. for my efis panels, lenght must me 15mm.

Step 3: Using a screwdriver, lift the four lids, Be careful with the balls and spring. They could jump away on disassembly..

Now the 2mm plastic axle is shown.

Inner portion of the switch (disassembled).

Step 5: Repeat the hole with a classic 1.6 mm drill until the end of the 6mm black plastic shaft we cut before.

Step 6: Drill a 5 mm diameter brass cylinder using a 1.6mm drill bit until it goes through.

Step 7: Machine these until reaching 3 mm diameter.

Part finished the springs exert equel forces keeping the part centered, with the 1 mm calibrated rod passing through and moving freely..

Step 9: Cut each spring to 4 and half turns. For a softer feel, make it 4 turns. This way, assembly is easier.

Insert the 1mm rod, and everything is ready for spring and ball assembly. .

Rotary switch with a momentary concentric pushbutton mounted behind. This could be replaced by a knitter or a knitter with a pushbutton too. Three in one.

Finished and ready to use.

This is my EFIS mode selector panel with the rotaries and switches with concentric pushbuttons. Click on the image for a larger view.

  If you don't have the proper tooling, contact me, I cant help him.

Step 2: Drill a 1.1mm hole in the bach to a depth of about 10 mm or until you reach the cross-spring without taking the switch apart..

View of the spring-ball housing.

This is th backside of it with the 1.1mm drill.                                     

Step 4: Drill (using a 1.6mm precision drill), to center the hole until the spring housing..

The length of the drill bit has gone through the length of the black plastic shaft..                      

 Make as many holes as switches needed, about 12mm apart.

Machine the piece as shwn on the pics, with two parts of 2 mm diameter and 1.5 mm long on the edges. (Spring ends).

Step 8: Cut the original spring in two

Insert the part in th spring housing as shown, placing it in the middle of the housing.

Once we have the springs and the balls in place, we can assemble the rest of the switch.

In the PCBs I designed, I included the possibility of a rotary with a center pushbutton.

Hand tools needed.

Work finished. The big knob moves the first two digits of the transponder. The small one moves the last two.By FSkey of: www.fsbus.de Click on the image for a larger view.