Intermezzo – a new project

While processing the first test panel I realized that drilling the acrylic with good precision is not so easy and because my cockpit panels are smaller than real Boeing 737 ones the distances between some of the holes are small.
For the larger and rectangular holes in my test panel I used a manual jigsaw, which worked, but wasn’t very accurate either. And there are around 44 panels to be processed ….

In the last months I watched a lot of YouTube videos of cockpit builders and some of them use a CNC mill or router to process the panels, which guarantees a very good reproducability. Moreover such a machine will also make it easier to build a 737 throttle quadrant constructed from MDF plates and aluminum.
The throttle quadrant is the block in the middle of the cockpit with a.o the throttle handles (that move automatically when the autothrottle controls the speed).
Besides the throttle handles it contains many more functions like the brake handles, flaps handle (to increase or decrease the area of the wings), the reverser for reversing the direction of the exhaust streams of the motors for braking and the trim wheels for leveling the plane. Many of these handles are motor driven for autopilot and autothrottle operation.

One YouTube channel, has a lot of very instructive videos on building your own CNC mill. It uses a moving y-axis table and a fixed vertical portal.
With this design I expect to achieve an acceptable precision and construction looked relatively easy because it is built with slotted aluminum beams and very rigid THK KR33 linear actuators. The latter are very high precision industrial quality and second hand ones are occasionally sold on Ebay.

THK KR33 linear actuator
THK KR33 linear actuator

kr33_500_02 kr33_500_01

David Burrell from Neo7cnc has designed a number of connection plates for easy and very precise connection of the linear actuators and beams.
When there is enough demand he has these processed at a professional CNC shop.
Unfortunately it turned out that the alumninum beams that he used for his machine are difficult to get for a reasonable price in Europe (shipping costs are really high).

While searching the internet I came across the site This builders site has a plethora of 3D printer, CNC mill and other build-it-yourself machine examples.
The associated internet shop sells slotted aluminum beams similar to the mentioned ones and a lot of other construction parts.
They also sell components to create linear actuators, but I had already purchased the THK ones.





For the stepper motors I bought a Chinese kit on Ebay containing 3 Waitan Nema-23 motors, driver board and power supply. Beware for some of the (blue) driver boards found on Ebay though: on YouTube a number of videos can be found of people who had many hardware patches on these boards and in the end still decided to go for another solution because they have a lot of problems.

The SainSmart CNC TB6560 3 Axis Stepper Motor Driver Controller Board that I have works excellent so far, but you need a PC with an original  parallel port to interface with it.

Sainsmart 3 axis control board
Sainsmart 3 axis control board

mach3 CNC TB6560 4 Axis Stepper Motor Controller


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