Here is my attempt at replicating the pushbutton insert for the IBM SYSTEM/360 and System/370 mainframe computers that were popular during the mid-1960s to late 1970s. These machines had operator consoles with numerous switches, lights and buttons ('blinkenlights') that all good computers had back then.
A number of pre-generated insert STL files are provided that are from SYSTEM/360 however if you want to do your own custom lable then proceed as follows..
In the OpenSCAD parametric script you can choose which pushbutton insert to produce, by uncommenting one (and one only at a time) button module between the START HERE and END HERE section. Comment out the Demo line first.
Hit F5 to colour render, and then F6 to finish render before hitting the Generate STL button.
PLA tests came out very well. ABS was very good too, but if using ABS check for dimensional accuracy (to width and height, given in the script) so they don't jam in the console panel, you may need to scale between 98% to 102% and run some test prints.
Print all inserts at 100% infill, especially the translucent one.
The ABS blue I have is too light compared to the real IBM blue. However the translucent grey was done in clear ABS and it isn't too bad (I have never been able to print a clear item with clear ABS btw).
Print the special curve sanding block to sand the printing layers off the face of the insert.
Paint the text next using white oil-based enamel (eg. Humbrol, Tamiya etc.) for the opaque inserts, and black for the translucent insert. Do not worry about cleaning all the paint off the concave face to much as you are doing this as it will be removed in the next step.
Use wet and dry sandpaper, used wet from #500 grade to #1200 grade and then polish.
The sanding photo shows #500 sandpaper being used. It is completely possible to get a very nice smooth finish on the button face if time and care is taken.
Button insert text
This is a WORK IN PROGRESS thing, and I still have experimentation to do to get the font more accurate. The default font in the text library text_on_OpenSCAD (see see https://github.com/t-paul/text_on_OpenSCAD) is used to position the lines angularly (circumferentially) into the curved concave face.
I've generated the STL's for all these button inserts and the sanding block and added them here, so you don't need to run the OpenSCAD script.
I hope to replicate the indicator inserts which were backlit only (not a pushbutton) and had two parallel black lines above and below the text to indicate this, eg. on 3420 tape units, card readers etc.