I am starting to think you purposefully seek old cheap / needy TE just so you can have an excuse to play with your 3D printer to make this or that custom part...
I am interested in just how good I can make a button look. Vince - if I can make it look like the original gloss plastic button I'll show you and see if I can get you approval. If I can then, I will have achieved what I once thought was impossible. ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Wow I didn't think I was seen as being so anal... oh well. I just like to make things as good as possible... within reason. If you can make something noticeably better with a small to moderate investment in time (learning curve / experimentation ) and money (tooling/supplies)... then why not try it...
OK so the two main things I would try to improve on your knobs, what jumps at me, are :
- White dot is too big, larger diameter than the original. Either too much paint, or you did not measure it accurately enough, or you did but the printer did not manage to do it properly in which case you need to compensate for that by asking it to make a smaller diameter so that once printed it ends up at the appropriate diameter.
- On your first pic the narrow side of the button is clearly undulating like mad, not straight at all. I guess it's inevitable with a 3D printer that melts plastic.... maybe printing the button more slowly would improve it, but you will always get ridges anyway, even if the overall shape is straight, as can be seen on the underside of the button.
So... I guess the only way to "clean up" these ridges and undulation is to mill the part on all 4 sides.
I guess you don't have a milling machine but maybe if you have a drill press, you could buy a little milling tool that you can mount like it were a drill bit. That must exist somewhere...
Well you could do it by hand (with the part held in place in a vice at least...) with a rasp. When I did my training in aviation, making custom aluminium parts by hand, we had a special rasp we called " râpe à Dural ". The "teeth" were shaped like circles/arcs, what you would get if you had put the part in a milling machine. It was like milling.. but with a hand tool. So you could easily make an edge or surface perfectly straight and smooth, was great. I don't know how it's called in English....
Top side of the knob being concave, that won't work, so maybe remove imperfections by hand as best you can with a scalpel, or simply with wet sanding at increasingly fine grit, until smooth enough to be painted. Actually since the button is small, you could do it all maybe with sand paper. Like you do when you sharpen wood working tools : you glue the sand paper flat onto a hard & flat surface, like say an old mirror or something. You secure that to your bench, then you work the button faces flat onto that sand paper... You need to try everything see what works best !
![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
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