Reverse engineering a Junghans J9 movement, last update 15.08.2019 - Helicopters, pocket watches, flight simulation, tools.

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Reverse engineering a Junghans J9 movement, last update 15.08.2019

Workshop > Projects
On this site I will display the process of reverse engineering the Junghans J9 movement. The goal is to make a acrylic main plate and a 3:1 3D printable function model.
This is my Stepcraft D300 fitted with a Andonstar USB microscope for precise measureing of the watch parts.
I can use my Sherline collet equipment on the Stepcraft to hold the watch parts.
Just a reminder how small the parts are.
The Andonstar microscope makes it possible to measure distances up to one hundredths of a millimeter.
The biggest challange sofar is the workflow in Fusion360. There are a lot of coordinates and measurements to deal with and on the main plate I put every point on one sketch. This needs to be changed as I lost the overview. It is almost not possible to find specific points again if they need adjaustments.
With the use of the CNC machine I get XY coordinates as perceise as to the machines specifications. Using these coordinates as such within Fusion360 is possible, but it get's very confusing as it is all releated to a 0/0 point. A better way, in my opinion, is to use the old method using circles to construct the points. Therefor I convert the XY coordinates into distances which can be easily used to construct the intersections for a needed centerpoint. I made a excel spreadsheet to calculate the distances.
As the minute wheel and the second wheel have defined fixed position it is always possible to contruct the other centerpoints with three circles. Another advantage of this method is that I do not need to align the movement plate on the CNC machine with a reference. I just put the plate in the movement holder and start centering the crosshair over the relevant point, hit ESC, which copies the current coordinate into the memory, and move to the next ponit, hit ESC and so forth. When finished I save the coordinate file for further use.
Below the current project status rendering from Fusion360
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