Mk-III

Progress on the Mk-III panel. My version is a combination of the SCU09 and the “Coffin” set photos from the Bletchley Park museum:  

The panel layout I used is being fabricated to test out a home made CAM machine.  But here are the results of the first proto layout from this weekend in the shop:



Mk-III Panel - test fit



There are a few minor adjustments need to be made; First the counter sinks were too deep for #4 hardware, but that was just operator error  - I forgot to reset the drill press depth screw from the #6 holes.   Secondly, the bottom screw on the panel to the lower left of the bottom dial - which is  intended to be a ground tie point for the "Aerial" capacitor to the panel shield -is much too close to the chassis to fit a nut and solder lug is just a simple adjustment to the drawing.  



Mk-III Panel Proto with Finish



The only other issue we are running into is the letters, in order to use white lettering we intend to use the CAM machine to engrave the letters and I will fill with white paint.



Mk-III Lettering



These need to be “kerned” or spaced a little to allow for the thickness of the tool.  The other issue is the “Futura” font used is not available on the CAM software and it seems to be drawing outlines which makes for a thick letters, so we can not use the lettering feature.  But with a .DXF file the font does not matter, it is all just lines and curves.

Here is the result with  a DXF file.  It is only a test panel with some OSB material, and the engraving is filled with drywall mud to test ...but it looks like a very good start!