Pull to turn switch

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2. February 2023 by Peter

In my remake of the Main Instrument Panel I have spent countless hours on making a “pull to turn” switch for the Autobrake switch.

In the aircraft the MAX position is guarded for safety reasons. You can turn the knob till ‘3’. But then you need to pull the switch to turn ti further to the MAX position.

I wanted to have that function in my cockpit so I started designing in Fusion360. It has taken quite many prototypes to make a working version. A push-to-turn is fairly simple. But the design of the pull function took many iterations to get right. Once the basis functions were there is was a matter if tweaking the different parameters and sizes to make it fit and still be strong enough.

Here is what I have ended up with. You need:

  • a 1x 45 deg. rotary switch with a D-shaped shaft (6.35 mm). The D-shape is important as it is the flat part that turns the shaft.
    I recommend the C&K A12515RNZQ.
  • 4 sets of (brass) spacers in these lengths: 5 mm, 20mm (or 1×25), 30mm + 4 nuts and washers
  • 1x spring 18mm long 7 mm bore/inner width

A lot of the tweaking had to do with the correct diameter to fit the shaft. This might come down to my printer. So here is a disclaimer: The STL-files are made to they fit when I print them. If my 3d-printer or your 3d-printer is calibrated differently the shaft might not fit. In that case I have included the Fusion360 file and you can alter/tweak the different parts of the model as you like.
Be aware that I not am able to help with altering the fusion360 filt to match your need. But I have made small video to show what you need to do. It is not that difficult. Remember you can get a free Fusion360-license for home use.


In order to print this you need to download the 4 .stl files below. If you need to alter the files (Like change the diameter of the shaft) you can do that in Fusion360 using the Fusion360-file

How to edit the shaft diameter in Fusion360

Watch this video to see how you edit the diameter of the printed shaft.

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About BuildaBoeing

My name is Peter and I live in Denmark.
I am building the cockpit of a Boeing 737 in my basement using my limited skills and inspiration from fellow builders.
I post my progress on this blog and hope it can be an inspiration to others.

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