C172 Mix lever
This page is split into three main sections:
Parts Guide
Print Guide
Build Guide
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This design was a real challenge from the start. The main aim was to allow for micro-adjustment and rapid lever adjustment. This would allow the unit to operate like a real aircraft. Hidden in the centre section is a screw thread in which a 3mm ball bearing runs. The lever can be operated in course adjustment by pushing the end button. For fine adjustment, the knob is turned clockwise or anticlockwise. This build will require metal rods and tubes, which can not be 3d printed. Check out the parts guide.
General Information:
Build Guide
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STEP:
1
Place the 10K ohm linear potentiometer onto the Pot Base (1). Secure with Qty4, M3 x 6mm screws.
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STEP:
2
Next, we need to create the Rod assy with the micro-adjustment. Some people might find this a little taxing. Refer to the PDF:
https://031b6b45-11f6-46a7-ab8e-17be9aef4dad.usrfiles.com/ugd/031b6b_8b9898e3353043658477b0e79cfbda8e.pdf
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STEP:
3
Drill a 3.5mm hole in the tube at the dimensions shown in the PDF.
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STEP:
4
I highly recommend brass or aluminium for this 4mm diameter rod. Steel can be used, but not stainless steel. This is because cutting a thread on each end becomes harder with each material upgrade. The filed section in the middle is easy to achieve. Use a file slanted to around 30 degrees. Ensure the serrated side of the file is used against the rod. Dont go too deep. Keep fitting the rod inside the tube, Place the ball bearing into the slot. The bearing need to sit flush or just below the surface of the outer tube. The ball bearing is 3mm in diameter or can be obtained by taking the bearings out of a rotary switch.
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STEP:
5
When the rod is pushed into the tube, the bearing needs to sit flush like this
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STEP:
6
When the rod is pulled, the bearing needs to ride up out of the hole,
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STEP:
7
Allow the bearing to sit fully in the hole, Insert the rod assy into the mix screw (2)
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STEP:
8
Insert the Ferrule assy (8) onto the outer tube. Secure with M3 x 6mm grub screws.
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STEP:
9
Place an M4 nut on the rod. This becomes the rod stop. There should be enough room for nuts to allow the position of the rod to be adjusted.
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STEP:
10
Place the Mix knob (3) onto the brass outer tube. Secure with M3 x 6mm grub screws.
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STEP:
11
Place spring at the end of the knob (3). this comes from an amazon assorted spring box. Select one that you feels provides the right feel and is strong enough to ensure it moves the rod and bearing up. You may need to use two smaller springs to achieve the correct force required.
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STEP:
12
Screw the Push Button onto the rod.
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STEP:
13
When the push button (4) is released, the spring pulls the rod out, causing the bearing to rise into the screw thread of the body. This allows for micro-adjustment of the mixing lever. By turning the mixing lever, the ball bearing ride in the reverse thread screwing the lever in or out depending on the direction of rotation.
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STEP:
14
Pushing the button in against the spring allows the bearing to fall inside the tube, disengaging from the screw thread. The mixing lever can now be pushed in and out easily.
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STEP:
15
Attach the pot base and clamp (7) with Qty 4, M4 x 30mm screws.
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STEP:
16
The unit is ready to be fitted to the sim.